Light emitting diode having electrode pads

ABSTRACT

A substrate, a first conductive type semiconductor layer arranged on the substrate, a second conductive type semiconductor layer arranged on the first conductive type semiconductor layer, an active layer disposed between the first conductive type semiconductor layer and the second conductive type semiconductor layer, a first electrode pad electrically connected to the first conductive type semiconductor layer, a second electrode pad arranged on the second conductive type semiconductor layer, an insulation layer disposed between the second conductive type semiconductor layer and the second electrode pad, and at least one upper extension electrically connected to the second electrode pad, the at least one upper extension being electrically connected to the second conductive type semiconductor layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and, claims the benefits andpriorities to, U.S. patent application Ser. No. 14/645,227, filed onMar. 11, 2015, which is a continuation of U.S. patent application Ser.No. 14/231,043, filed on Mar. 31, 2014, which is a continuation of U.S.patent application Ser. No. 13/862,713, filed on Apr. 15, 2013 andissued as U.S. Pat. No. 8,742,449, which is a continuation of U.S.patent application Ser. No. 13/617,810, filed on Sep. 14, 2012 andissued as U.S. Pat. No. 8,436,369, which is a continuation of U.S.patent application Ser. No. 12/974,917, filed on Dec. 21, 2010 andissued as U.S. Pat. No. 8,309,971, and claims priorities from and thebenefits of Korean Patent Application No. 10-2010-0001089, filed on Jan.7, 2010, Korean Patent Application No. 10-2010-0001090, filed on Jan. 7,2010, Korean Patent Application No. 10-2010-0001204, filed on Jan. 7,2010, Korean Patent Application No. 10-2010-0001205, filed on Jan. 7,2010, Korean Patent Application No. 10-2010-0001408, filed on Jan. 7,2010, Korean Patent Application No. 10-2010-0001813, filed on Jan. 8,2010, Korean Patent Application No. 10-2010-0003396, filed on Jan. 14,2010, Korean Patent Application No. 10-2010-0003964, filed on Jan. 15,2010, and Korean Patent Application No. 10-2010-0003965, filed on Jan.15, 2010, which are hereby incorporated by reference for all purposes asif fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

Exemplary embodiments of the invention relate to light emitting diodesand, more particularly, to light emitting diodes having electrode pads.

Description of the Background

Gallium nitride (GaN) based light emitting diodes (LEDs) have been usedin a wide range of applications including full color LED displays, LEDtraffic signals, white light LEDs, etc.

A GaN-based light emitting diode may generally be formed by growingepitaxial layers on a substrate, for example, a sapphire substrate, andinclude an N-type semiconductor layer, a P-type semiconductor layer, andan active layer interposed between the N-type semiconductor layer andthe P-type semiconductor layer. Further, an N electrode pad is formed onthe N-type semiconductor layer and a P electrode pad is formed on theP-type semiconductor layer. The light emitting diode is electricallyconnected to and operated by an external power source through theseelectrode pads. Here, electric current is directed from the P-electrodepad to the N-electrode pad through the semiconductor layers.

Generally, since the P-type semiconductor layer may have a highresistivity, electric current may not be evenly distributed in theP-type semiconductor layer, but may be concentrated on a portion of theP-type semiconductor layer where the P-electrode pad is formed, andelectric current may be concentrated on and flow through edges of thesemiconductor layers. This may be referred to as current crowding, andmay lead to a reduction in light emitting area, thereby deterioratingluminous efficacy of the light emitting source. To solve such problems,a transparent electrode layer having a low resistivity may be formed onthe P-type semiconductor layer so as to enhance current spreading. Inthis structure, when supplied from the P-electrode pad, the electriccurrent may be dispersed by the transparent electrode layer beforeentering the P-type semiconductor layer, thereby increasing a lightemitting area of the LED.

However, since the transparent electrode layer tends to absorb light,the thickness of the transparent electrode layer may be limited, therebyproviding limited current spreading. In particular, in a large LEDhaving an area of about 1 mm² or more for high output, there may be alimit in achieving efficient current spreading through the transparentelectrode layer.

To facilitate current spreading within the light emitting diode,extensions extending from the electrode pads may be used. For example,U.S. Pat. No. 6,650,018, issued to Zhao, et al., discloses an LED whichincludes a plurality of extensions extending from electrode contactportions, that is, electrode pads, in opposite directions to enhancecurrent spreading.

Although the use of such extensions may enhance current spreading over awide region of the LED, current crowding may still occur at portions ofthe LEDs where the electrode pads are formed.

Moreover, as the size of the LED increases, the likelihood of a defectbeing present in the LED may increase. Defects such as threadingdislocations, pin-holes, etc. provide a path through which electriccurrent may flow, thereby disturbing current spreading in the LED.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention provide a light emittingdiode which prevents current crowding near an electrode pad.

Exemplary embodiments of the present invention also provide a largelight emitting diode which permits uniform current spreading over a widearea.

Exemplary embodiments of the present invention also provide a lightemitting diode which includes an electrode pad spaced apart from asemiconductor layer.

Exemplary embodiments of the present invention also provide a lightemitting diode with a semiconductor stack structure that may be dividedinto a plurality of regions.

Exemplary embodiments of the present invention also provide lightemitting diodes having various structures of electrode pads andextensions capable of enhancing current spreading.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

An exemplary embodiment of the present invention discloses a lightemitting diode including a substrate, a first conductive typesemiconductor layer arranged on the substrate, a second conductive typesemiconductor layer arranged on the first conductive type semiconductorlayer, an active layer disposed between the first conductive typesemiconductor layer and the second conductive type semiconductor layer,a first electrode pad electrically connected to the first conductivetype semiconductor layer, a second electrode pad arranged on the secondconductive type semiconductor layer, an insulation layer disposedbetween the second conductive type semiconductor layer and the secondelectrode pad; and at least one upper extension electrically connectedto the second electrode pad, the at least one upper extension beingelectrically connected to the second conductive type semiconductorlayer.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a plan view of a light emitting diode according to a firstexemplary embodiment of the present invention.

FIG. 2a is a cross-sectional view taken along line A-A of FIG. 1.

FIG. 2b is a cross-sectional view taken along line B-B of FIG. 1.

FIG. 3 is a cross-sectional view of a light emitting diode according toa second exemplary embodiment of the present invention.

FIG. 4 is a plan view of a light emitting diode according to a thirdexemplary embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a light emitting diodeaccording to a fourth exemplary embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a light emitting diodeaccording to a fifth exemplary embodiment of the present invention.

FIG. 7 is a plan view of a light emitting diode according to a sixthexemplary embodiment of the present invention.

FIG. 8 is a plan view of a light emitting diode according to a seventhexemplary embodiment of the present invention.

FIG. 9 is a plan view of a light emitting diode according to an eighthexemplary embodiment of the present invention.

FIG. 10 is a plan view of a light emitting diode according to a ninthexemplary embodiment of the present invention.

FIG. 11 is a plan view of a light emitting diode according to a tenthexemplary embodiment of the present invention.

FIG. 12 is a plan view of a light emitting diode according to aneleventh exemplary embodiment of the present invention.

FIG. 13 is a plan view of a light emitting diode according to a twelfthexemplary embodiment of the present invention.

FIG. 14 is a plan view of a light emitting diode according to athirteenth exemplary embodiment of the present invention.

FIGS. 15a, 15b and 15c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 14, respectively.

FIG. 16 is a cross-sectional view of a light emitting diode according toa fourteenth exemplary embodiment of the present invention.

FIGS. 17a, 17b, 17c and 17d are plan views illustrating a method ofmanufacturing a light emitting diode according to the thirteenthexemplary embodiment of the present invention.

FIG. 18 is a plan view of a light emitting diode according to afifteenth exemplary embodiment of the present invention.

FIG. 19 is a plan view of a light emitting diode according to asixteenth exemplary embodiment of the present invention.

FIG. 20 is a plan view of a light emitting diode according to aseventeenth exemplary embodiment of the present invention.

FIGS. 21a, 21b and 21c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 20, respectively.

FIGS. 22a, 22b, 22c and 22d are plan views illustrating a method ofmanufacturing a light emitting diode according to the seventeenthexemplary embodiment of the present invention.

FIG. 23 is a plan view of a light emitting diode according to aneighteenth exemplary embodiment of the present invention.

FIGS. 24a, 24b and 24c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 23, respectively.

FIGS. 25a, 25b, 25c, 25d and 25e are plan views illustrating a method ofmanufacturing a light emitting diode according to the eighteenthexemplary embodiment of the present invention.

FIG. 26 is a plan view of a light emitting diode according to anineteenth exemplary embodiment of the present invention.

FIG. 27 is a plan view of a light emitting diode according to atwentieth exemplary embodiment of the present invention.

FIG. 28 is a plan view of a light emitting diode according to atwenty-first exemplary embodiment of the present invention.

FIGS. 29a, 29b and 29c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 28, respectively.

FIGS. 30a, 30b, 30c, 30d and 30e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-firstexemplary embodiment of the present invention.

FIG. 31 is a plan view of a light emitting diode according to atwenty-second exemplary embodiment of the present invention.

FIGS. 32a, 32b and 32c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 31, respectively.

FIGS. 33a, 33b, 33c, 33d and 33e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-secondexemplary embodiment of the present invention.

FIG. 34 is a plan view of a light emitting diode according to atwenty-third exemplary embodiment of the present invention.

FIGS. 35a, 35b and 35c are cross-sectional views taken along lines A-A,B-B and C-C of FIG. 34, respectively.

FIGS. 36a, 36b, 36c, 36d and 36e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-thirdexemplary embodiment of the present invention.

FIG. 37 is a plan view of a light emitting diode according to atwenty-fourth exemplary embodiment of the present invention.

FIG. 38 is a plan view of a light emitting diode according to a twentyfifth exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which exemplary embodiments of the inventionare shown. This invention may, however, be embodied in many differentforms and should not be construed as limited to the exemplaryembodiments set forth herein. Rather, these exemplary embodiments areprovided so that this disclosure is thorough and will fully convey thescope of the invention to those skilled in the art. In the drawings, thesizes and relative sizes of layers and regions may be exaggerated forclarity. Like reference numerals in the drawings denote like elements.

It will be understood that when an element such as a layer, film, regionor substrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.

FIG. 1 is a plan view of a light emitting diode according to anexemplary embodiment of the present invention, FIG. 2a is across-sectional view taken along line A-A of FIG. 1, and FIG. 2b is across-sectional view taken along line B-B of FIG. 1.

Referring to FIGS. 1, 2 a and 2 b, the light emitting diode includes asubstrate 21, a first conductive type semiconductor layer 23, an activelayer 25, a second conductive type semiconductor layer 27, an insulationlayer 31, first and second electrode pads 35, 33, and upper extensions33 a. The light emitting diode may further include connectors 33 b, atransparent electrode layer 29, a first lower extension 35 a, and asecond lower extension 35 b. The substrate 21 may be a sapphiresubstrate, but is not limited thereto. The substrate 21 has asubstantially quadrangular shape to have corners in diagonal directions.

The first conductive type semiconductor layer 23 is located on thesubstrate 21 and the second conductive type semiconductor layer 27 islocated on the first conductive type semiconductor layer 23 with theactive layer 25 interposed between the first conductive typesemiconductor layer 23 and the second conductive type semiconductorlayer 27. The first conductive type semiconductor layer 23, active layer25 and second conductive type semiconductor layer 27 may be formed of,but are not limited to, a GaN-based compound semiconductor material suchas (Al, In, Ga)N. The active layer 25 is composed of elements emittinglight at desired wavelengths, for example, ultraviolet (UV) or bluelight.

The first conductive type semiconductor layer 23 may be an n-typenitride semiconductor layer and the second conductive type semiconductorlayer 27 may be a p-type nitride semiconductor layer, or vice versa.

As shown in the figures, the first conductive type semiconductor layer23 and/or the second conductive type semiconductor layer 27 may have asingle layer structure or a multilayer structure. Further, the activelayer 25 may have a single quantum well structure or a multi-quantumwell structure. The light emitting diode may further include a bufferlayer (not shown) between the substrate 21 and the first conductive typesemiconductor layer 23. The first conductive type semiconductor layer23, active layer 25, and second conductive type semiconductor layer 27may be formed by metal organic chemical vapor deposition (MOCVD) ormolecular beam epitaxy (MBE) technique.

A transparent electrode layer 29 may be formed on the second conductivetype semiconductor layer 27. The transparent electrode layer 29 may beformed of indium tin oxide (ITO) or Ni/Au and forms an ohmic contactwith the second conductive type semiconductor layer 27.

The second conductive type semiconductor layer 27 and the active layer25 may be subjected to a patterning process to expose a region(s) of thefirst conductive type semiconductor layer 23 via photolithography andetching. Such a process is generally known as mesa-etching. Mesa-etchingmay provide divided light emitting regions as shown in FIGS. 1 and 2.Although, in the present exemplary embodiment, the light emitting diodehas two light emitting regions that are isolated from each other, thelight emitting diode may have more than two separate light emittingregions. Further, the mesa-etching may be performed to form inclinedside surfaces which have a degree of inclination in the range of 30-70degrees relative to a substrate plane relative to a plane of thesubstrate 21.

The first and second electrode pads 35, 33 are located on the region(s)of the first conductive type semiconductor layer 23, which is exposedthrough the mesa-etching. The first electrode pad 35 is electricallyconnected to the first conductive type semiconductor layer 23. Thesecond electrode pad 33 is insulated from the first conductive typesemiconductor layer 23 by the insulation layer 31. The first and secondelectrode pads 35, 33 are bonding pads for wire bonding and may have anarea sufficiently wide for wire bonding. The first and second electrodepads 35, 33 may be formed on the exposed region(s) of the firstconductive type semiconductor layer 23, but are not limited thereto.

The insulation layer 31 is disposed between the second electrode pad 33and the first conductive type semiconductor layer 23 to insulate thesecond electrode pad 33 from the first conductive type semiconductorlayer 23. Further, the insulation layer 31 may cover the side surfacesof the second conductive type semiconductor layer 27 and the activelayer 25 exposed through the mesa-etching to. The insulation layer 31may extend to an upper surface of the second conductive typesemiconductor layer 27 such that an edge of the insulation layer 31overlaps the second conductive type semiconductor layer 27.Alternatively, the insulation layer 31 may extend to cover the secondconductive type semiconductor layer 27, and in this case, the insulationlayer 31 may have a via-hole formed at an upper portion of the secondconductive type semiconductor layer 27 or the transparent electrodelayer 29.

The upper extensions 33 a are located on the second conductive typesemiconductor layer 27 (or the transparent electrode layer 29). Theupper extensions 33 a may be connected to the second electrode pad 33via connectors 33 b, respectively, and may be electrically connected tothe second conductive type semiconductor layer 27. When the insulationlayer 31 covers the second conductive type semiconductor layer 27, theupper extensions 33 a are connected to the second conductive typesemiconductor layer 27 (or the transparent electrode layer 29) through avia-hole in the insulation layer 31. The upper extensions 33 a aredisposed to allow uniform current spreading in the second conductivetype semiconductor layer 27. The connectors 33 b are separated from theside surfaces of the transparent electrode layer 29, the secondconductive type semiconductor layer 27, and the active layer 25 by theinsulation layer 31. The insulation layer 31 is disposed between thetransparent electrode layer 29, the second conductive type semiconductorlayer 27, and the active layer 25 and the second electrode pad 33 suchthat the second electrode pad 33 does not physically contact thoselayers. The insulation layer 31 may prevent current from being conducteddirectly from the second electrode pad 33 into the transparent electrodelayer 29, the second conductive type semiconductor layer 27, or theactive layer 25.

The first lower extension 35 a may extend from the first electrode pad35. The first lower extension 35 a is located on the first conductivetype semiconductor layer 23 and electrically connected thereto. As shownin the figures, the first lower extension 35 a may be located betweenthe divided light emitting regions and extend towards the secondelectrode pad 33. Alternatively, the second lower extension 35 b mayextend from the first electrode pad 35. The second lower extension 35 bis located on the first conductive type semiconductor layer 23 andelectrically connected to the first conductive type semiconductor layer23, and extend along an edge of the substrate 21 to be located outsidethe light emitting regions.

As shown in the present exemplary embodiment as well as the followingexemplary embodiments, the lower extension 35 a and the upper extension33 a may be arranged in specific patterns to help improve currentspreading. For example, in the present exemplary embodiment, having twoupper extensions 33 a extend from the second electrode pad 33 along eachof the divided light emitting regions may improve current spreadingwhile not requiring multiple electrode pads on the light emitting diodeto connect to the upper extensions 33 a. In the various exemplaryembodiments, the lower extension and upper extension arrangement maylikewise improve current spreading in divided light emitting regionswhile avoiding a requirement for multiple electrode pads on the singlesubstrate.

The electrode pads 33, 35, the upper extensions 33 a, the connectors 33b, and the lower extension 35 a may be formed of, but are not limitedto, the same material, for example Cr/Au, by the same process.Alternatively, the upper extensions 33 a and the second electrode pad 33may be formed of different materials by different processes.

In the present exemplary embodiment, the divided light emitting regionshave a symmetrical structure relative to a line, for example, a cut lineB-B, which is located between the first electrode pad 35 and the secondelectrode pad 33. The upper extensions 33 a are also symmetricallydisposed, so that the light emitting regions may exhibit the sameluminescence characteristics. Accordingly, when a light emitting regionis divided into two light emitting regions in a single light emittingdiode, a process of packaging the light emitting diode may be furthersimplified compared to using two light emitting diodes connected inparallel to each other. Furthermore, the divided light emitting regionsmay relieve current crowding caused by defects and may improve lightextraction efficiency through formation of the inclined side surfaces bymesa-etching.

FIG. 3 is a cross-sectional view of a light emitting diode according toa second exemplary embodiment of the present invention.

Referring to FIG. 3, the light emitting diode of the present exemplaryembodiment is generally similar to the light emitting diode describedwith reference to FIGS. 1 and 2. In the light emitting diode of thepresent exemplary embodiment, however, a portion of a second electrodepad 43 is located above a second conductive type semiconductor layer 27.

Specifically, the second electrode pad 43 is located on an exposedregion of a first conductive type semiconductor layer 23 subjected tomesa-etching process such that a portion of the second electrode pad 43is located above the second conductive type semiconductor layer 27. Thesecond electrode pad 43 is insulated not only from the first conductivetype semiconductor layer 27 but also from the transparent electrodelayer 29, the second conductive type semiconductor layer 27, and theactive layer by an insulation layer 31. Thus, the second electrode pad43 does not physically contact those layers. Extensions 33 a may bedirectly extended from the second electrode pad 43 or may be extendedtherefrom with a connector disposed therebetween.

In the present exemplary embodiment, the second electrode pad 43 isinsulated from the semiconductor layers by the insulation layer 31,which may thereby prevent current crowding around the second electrodepad 43. Furthermore, in the present exemplary embodiment, an areasubjected to mesa-etching may be decreased compared to the previousexemplary embodiment, thereby increasing the light emitting region.

FIG. 4 is a plan view of a light emitting diode according to a thirdexemplary embodiment of the present invention.

Referring to FIG. 4, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIGS. 1 and 2. In the light emitting diode of the presentexemplary embodiment, however, a first electrode pad 55 and a secondelectrode pad 53 are arranged in a different manner than in the aboveexemplary embodiments.

In the above exemplary embodiment shown in FIGS. 1 and 2, the first andsecond electrode pads 35, 33 are disposed at the centers of edges of thesubstrate 21 to face each other. In the light emitting diode accordingto the present exemplary embodiment, first and second electrode pads 55,53 are diagonally disposed near corners of the substrate 21 to face eachother.

As the first electrode pad 55 and the second electrode pad 53 arerespectively disposed near the corners of the substrate 21, it ispossible to form the first and second electrode pads 55, 53 a relativelylarge distance from each other.

In the present exemplary embodiment, upper extensions 53 a may extendalong an edge of the substrate 21 from the second electrode pad 53. Theupper extensions 53 a are connected to the second conductive typesemiconductor layer 27 or the transparent electrode layer 29 and arealso connected to the second electrode pad 53 through connectors 53 b.The connectors 53 b are insulated from the second conductive typesemiconductor layer 27 by an insulation layer 31. In addition, theinsulation layer 31 covers side surfaces of the second conductive typesemiconductor layer 27 and active layer 25.

A first lower extension 55 a extends from the first electrode pad 55towards the second electrode pad 53 and is electrically connected to thefirst conductive type semiconductor layer 23. The first lower extension55 a may be diagonally located on the substrate 21, and the secondconductive type semiconductor layer 27 and active layer 25 may bedivided into two light emitting regions isolated from each otherrelative to the first lower extension 55 a. Accordingly, the first lowerextension 55 a is located between the light emitting regions. Inaddition, a second lower extension 55 b may extend along an edge of thesubstrate 21 from the first electrode pad 55.

As described with reference to FIGS. 1 and 2, the second electrode pad53 is located on the first conductive type semiconductor layer 23 withthe insulation layer 31 disposed between the second electrode pad 53 andthe first conductive type semiconductor layer 23. As such, since thesecond electrode pad 53 is separated from the second conductive typesemiconductor layer 27, it is possible to prevent current crowdingaround the second electrode pad 53.

Furthermore, as described with reference to FIG. 3, a portion of thesecond electrode pad 53 may be located on the second conductive typesemiconductor layer 27.

FIGS. 5 and 6 are partial cross-sectional views of a light emittingdiode according to fourth and fifth exemplary embodiments of the presentinvention.

In the above exemplary embodiments, the second electrode pad 33 or 53 islocated on the first conductive type semiconductor layer 23 with theinsulation layer 31 disposed between the second electrode pad 33 or 53and the first conductive type semiconductor layer 23. In the fourthexemplary embodiment, however, a second electrode pad 63 may be locateddirectly on a substrate 21 (see FIG. 5). Further, in the fifth exemplaryembodiment, an insulation layer 31 may be disposed between the substrate21 and the second electrode pad 63 (see FIG. 6). That is, with theinsulation layer 31 located directly on the substrate 21, the secondelectrode pad 63 may be located directly on the insulation layer 31 tobe in contact with the insulation layer 31. The second electrode pad 63is formed on a region from which the first conductive type semiconductorlayer 23, active layer 25 and second conductive type semiconductor layer27 formed on the substrate 21 have been partially removed. When thesecond electrode pad 63 is formed directly on the substrate 21 to be incontact with the substrate 21, the substrate 21 may be a dielectricsubstrate.

In the above exemplary embodiments, the second electrode pad 33, 53 or63 is horizontally separated from the second conductive typesemiconductor layer 27. Consequently, it is possible to prevent currentcrowding around the second electrode pad. In addition, the secondelectrode pad 33, 53 or 63 is electrically connected to the upperextension 33 a or 53 a through the connector 33 b or 53 b, which isinsulated from the light emitting regions by the insulation layer 31.Since the connector 33 b, 53 b is also insulated from the secondconductive type semiconductor layer 27 by the insulation layer 31, it ispossible to prevent current crowding around the second electrode pad 33,53, or 63.

FIG. 7 is a plan view of a light emitting diode according to a sixthexemplary embodiment of the present invention.

Referring to FIG. 7, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIGS. 1 and 2. In the light emitting diode of the presentexemplary embodiment, however, a first pad 55 and a second electrode pad53 are arranged in a different manner than in the above exemplaryembodiment.

In the above exemplary embodiment shown in FIGS. 1 and 2, the first andsecond electrode pads 35, 33 are disposed near the edges of thequadrangular substrate 21 to face each other. In the light emittingdiode according to the present exemplary embodiment, a second electrodepad 153 is disposed at the center of the substrate 21. In addition, afirst electrode pad 155 may be disposed at an edge of the substrate.Furthermore, as shown in FIG. 7, a plurality of first electrode pads 155may be disposed on edges of the substrate to face each other.

As in the above exemplary embodiments, a second conductive typesemiconductor layer 27 and an active layer 25 may be divided into plurallight emitting regions. Herein, the second conductive type semiconductorlayer 27 and active layer 25 are divided into two light emitting regionsLE1 and LE2. An upper extension 153 a is located on the light emittingregions LE1, LE2, and connected to the second conductive typesemiconductor layer 27 by the insulation layer 31 (see FIGS. 2a and 2b). The insulation layer 31 may cover side surfaces of the secondconductive type semiconductor layer 27 and active layer 25 exposedthrough mesa-etching to insulate the connector 153 b or the secondelectrode pad 153 from the side surfaces of the second conductive typesemiconductor layer 27 and active layer 25.

A lower extension 155 b may extend from the first electrode pad 155along an edge of the substrate 21. As shown in FIG. 7, the lowerextension 155 b may extend along the edge of the substrate 21 tosurround the light emitting regions LE1, LE2. The lower extension 155 bis electrically connected to the first conductive type semiconductorlayer 23. An additional lower extension (not shown) may extend from thelower extension 155 b to a region between the light emitting regionsLE1, LE2.

Further, as described with reference to FIGS. 1 and 2, the secondelectrode pad 153 is located on the first conductive type semiconductorlayer 23 with the insulation layer 31 disposed between the secondelectrode pad 153 and the first conductive type semiconductor layer 23.As such, since the second electrode pad 153 is separated from the secondconductive type semiconductor layer 27, it is possible to preventcurrent crowding around the second electrode pad 153. Furthermore, asdescribed with reference to FIG. 3, a portion of the second electrodepad 153 may be located on the second conductive type semiconductor layer27.

According to the present exemplary embodiment, since the secondelectrode pad 153 is disposed at the center of the substrate 21, thatis, the light emitting diode, it is possible to achieve uniform currentspreading from the second electrode pad to the light emitting regionsLE1, LE2.

FIG. 8 is a plan view of a light emitting diode according to a seventhexemplary embodiment of the present invention.

Referring to FIG. 8, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIG. 7. In the light emitting diode of the presentexemplary embodiment, however, two upper extensions 153 a are located oneach of light emitting regions LE1, LE2, and a lower extension 155 cextends from each first electrode pad 155 towards a second electrode pad153.

Specifically, at least two upper extensions 153 a are located on each ofthe light emitting regions LE1, LE2. The upper extensions 153 a may bedisposed in a symmetrical structure relative to a line crossing thefirst electrode pad 155 and the second electrode pad 153. The upperextensions 153 a are connected to the second electrode pad 153 throughthe connectors 153 b, respectively.

The lower extension 155 c extends from the first electrode pad 155towards a region between the upper extensions 153 a, and is electricallyconnected to the first conductive type semiconductor layer 23. The lowerextension 155 c is terminated near the first electrode pad 155.

In the present exemplary embodiment, the light emitting regions LE1, LE2may be symmetrically disposed, thereby exhibiting the same luminescencecharacteristics.

According to the present exemplary embodiment, at least two upperextensions 153 a are disposed in each of the light emitting regions LE1,LE2, and the lower extension 155 c is located in the region between theupper extensions 153 a, thereby enhancing current spreading in the lightemitting regions, for example when the light emitting regions have awide area.

FIG. 9 is a plan view of a light emitting diode according to an eighthexemplary embodiment of the present invention.

Referring to FIG. 9, the second conductive type semiconductor layer 27and active layer 25 are divided into four light emitting regions LE1,LE2, LE3, LE4. Further, four first electrode pads 165 are disposed nearcorners of the light emitting diode, and a lower extension 165 bsurrounds the light emitting regions LE1, LE2, LE3, LE4.

As in the sixth and seventh embodiments, a second electrode pad 163 isdisposed at the center of the substrate 21. The second electrode pad 163may be located on a first conductive type semiconductor layer 23 with aninsulation layer 31 interposed therebetween.

Upper extensions 163 a are located on each of the light emitting regionsLE1, LE2, LE3, LE4. The upper extensions 163 a may extend along edges ofeach of the light emitting regions LE1, LE2, LE3, LE4 and be connectedto a second conductive type semiconductor layer 27 or a transparentelectrode layer 29. The upper extensions 163 a are connected to thesecond electrode pad 163 through connectors 163 b, which are insulatedfrom the light emitting regions LE1, LE2, LE3, LE4 by the insulationlayer 31.

According to the present exemplary embodiment, with the second electrodepad 163 located at the center of the substrate 21, a light emittingregion is divided into the plural light emitting regions LE1, LE2, LE3,LE4, so that the light emitting diode may achieve uniform currentspreading over a wide area.

In the present exemplary embodiment, the light emitting diode has thefour first electrode pads 165 disposed at four corners of the substrate21. Alternatively, the light emitting diode may have a single firstelectrode pad 165, from which the lower extension 165 b extends tosurround the light emitting regions LE1, LE2, LE3, LE4.

FIG. 10 is a plan view of a light emitting diode according to a ninthexemplary embodiment of the present invention.

Referring to FIG. 10, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIG. 9. In the light emitting diode of the presentexemplary embodiment, however, lower extensions 165 a, 165 b and upperextensions 163 a are arranged in a different manner than in the aboveexemplary embodiment.

Specifically, the lower extensions 165 b extend from first electrodepads 165 along an edge of the substrate 21 to surround associated lightemitting regions LE1, LE2, LE3, LE4, and are separated from each otherin some regions. Further, lower extensions 165 a extend into a regionbetween the light emitting regions LE1, LE2 and a region between thelight emitting regions LE3, LE4, respectively. The lower extensions 165a may extend from the lower extensions 165 b.

Each of the upper extensions 163 a is connected to the second electrodepad 163 through a connector 163 b. The upper extension 163 a extendsalong one edge of each of the light emitting regions LE1, LE2, LE3, LE4,and then extends towards an opposite edge of each of the light emittingregions in a region between the lower extensions 165 a, 165 b.

According to the present exemplary embodiment, the light emitting diodemay achieve optimized current spreading in the light emitting regionsLE1, LE2, LE3, LE4 by adjusting the distances between the lowerextensions 165 a, 165 b and upper extensions 163 a through adjustment ofshapes and arrangement thereof.

In the sixth to eighth exemplary embodiments, the second electrode pad153 or 163 is located on the first conductive type semiconductor layer23, and the insulation layer 31 is disposed between the second electrodepad 153 or 163 and the first conductive type semiconductor layer 23.However, as described above with reference to FIGS. 5 and 6, the secondelectrode 153 or 163 may be located directly on the substrate 21 (seeFIG. 5). Alternatively, the insulation layer 31 may be disposed betweenthe substrate 21 and the second electrode 153 or 163 (see FIG. 6). Thatis, with the insulation layer 31 directly located on the substrate 21,the second electrode pad 153 or 163 may be directly located on theinsulation layer 31 to be in contact with the insulation layer 31. Thesecond electrode pad 153 or 163 is formed on a region from which thefirst conductive type semiconductor layer 23, active layer 25 and secondconductive type semiconductor layer 27 formed on the substrate 21 havebeen partially removed. When the second electrode pad 153 or 163 isdirectly formed on the substrate 21 to be in contact with the substrate21, the substrate 21 may be a dielectric substrate.

FIG. 11 is a plan view of a light emitting diode according to a tenthexemplary embodiment of the present invention.

Referring to FIG. 11, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIGS. 1 and 2. In the light emitting diode of the presentexemplary embodiment, however, first and second electrode pads 255, 253are arranged in a different manner than in the above exemplaryembodiment.

Specifically, in FIGS. 1 and 2, the first and second electrode pads 35,33 are disposed in a major axis direction of the substrate 21 to faceeach other. In the present exemplary embodiment, however, the secondelectrode pad 253 is disposed near the center of one edge of thesubstrate 21 and two first electrode pads 255 are disposed near theopposite edge of the substrate 21. The one edge of the substrate 21 maybe longer than other edges of the substrate 21, but is not limitedthereto. In addition, the first electrode pads 255 are not located toface the second electrode pad 253, but are disposed near ends of theopposite edge of the substrate 21, that is, corners of the quadrangularsubstrate 21.

As in the above exemplary embodiments, the second conductive typesemiconductor layer 27 and active layer 25 may be divided into lightemitting regions LE1, LE2. Herein, the second conductive typesemiconductor layer 27 and active layer 25 are divided into two lightemitting regions. The light emitting regions LE1, LE2 may be disposed ina symmetrical structure relative to a line extending from the secondelectrode pad 253 in a minor axis direction of the substrate 21. Inother words, the light emitting regions LE1, LE2 may be disposed in asymmetrical structure relative to a line crossing the second electrodepad 253 to be perpendicular to the one edge of the substrate 21.

An upper extension 253 a or 253 c is located on each of the lightemitting regions LE1, LE2. The upper extensions 253 c may be connectedto the second electrode pad 253 through a connector 253 b and extendalong one edge of the light emitting region LE1. The upper extensions253 a may extend linearly from the upper extensions 253 c. That is, theupper extensions 253 a may linearly extend from one edge of thesubstrate 21 towards the other edge thereof.

The connector 253 b is insulated from the second conductive typesemiconductor layer by the insulation layer 31 (see FIGS. 2a and 2b ).The insulation layer 31 may cover side surfaces of the second conductivetype semiconductor layer 27 and active layer 25 exposed by mesa-etchingto insulate the connector 253 b or the second electrode pad 253 from theside surfaces of the second conductive type semiconductor layer 27 andactive layer 25.

A lower extension 255 b may extend from the first electrode pads 255along edges of the substrate 21. As shown in FIG. 11, the lowerextension 255 b includes a lower extension extending along the otheredge of the substrate 21 and a lower extension extending along an edgethat connects the one edge to the other edge of the substrate.Accordingly, the lower extension 255 b may extend along two edges of thelight emitting region LE1 or LE2. In addition, another lower extension255 a may extend from the lower extension 255 b to a region between thelight emitting regions LE1, LE2. The lower extension 255 a may extendtowards the second electrode pad 253. The lower extensions 255 a, 255 bare electrically connected to the first conductive type semiconductorlayer 23 to assist current spreading in the light emitting diode.

Further, as described with reference to FIGS. 1 and 2, the secondelectrode pad 253 is located on the first conductive type semiconductorlayer 23 with the insulation layer 31 disposed between the secondelectrode pad 253 and the first conductive type semiconductor layer 23.As such, since the second electrode pad 253 is separated from the secondconductive type semiconductor layer 27, it is possible to preventcurrent crowding around the second electrode pad 253. Furthermore, asdescribed with reference to FIG. 3, a portion of the second electrodepad 253 may be located on the second conductive type semiconductor layer27.

According to the present exemplary embodiment, the light emittingregions LE1, LE2 share a single second electrode pad 253 and areprovided with the associated first electrode pads 255, respectively.Further, since the first electrode pads 255 are separated from thecenter of the edge of the substrate 21 such that the first electrodepads 255 and the second electrode pad 253 do not face each other, it ispossible to achieve more efficient current spreading in the respectivelight emitting regions LE, LE2.

In the present exemplary embodiment, the second conductive typesemiconductor layer 27 and active layer 25 are divided to define the twolight emitting regions LE1, LE2. However, it is not necessary to dividethe second conductive type semiconductor layer 27 and active layer 25.That is, the second conductive type semiconductor layer 27 and activelayer 25 of the light emitting regions LE1, LE2 may be connected to eachother.

FIG. 12 is a plan view of a light emitting diode according to aneleventh exemplary embodiment of the present invention.

Referring to FIG. 12, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIG. 11. However, the light emitting diode of the presentexemplary embodiment further includes a lower extension 255 c enteringeach of the light emitting regions LE1, LE2. In the present exemplaryembodiment, the lower extension 255 a of FIG. 11 may be omitted.

Each of the lower extensions 255 c is located on a region of the firstconductive type semiconductor layer 23 exposed through mesa-etching andis electrically connected to the first conductive type semiconductorlayer 23. The lower extension 255 c may extend from the extensions 255 btowards one edge of the substrate 21. On the other hand, each of theupper extensions 253 a extends to a region between the lower extensions255 b, 255 c.

According to the present exemplary embodiment, the light emitting diodeincludes the lower extensions 255 c each entering the light emittingregion LE1 or LE2, thereby achieving uniform current spreading overbroader light emitting regions.

In the present exemplary embodiment, the light emitting regions LE, LE2may be disposed in a symmetrical structure relative to a line crossingthe second electrode pad 253 to be perpendicular to the one edge of thesubstrate 21. As a result, the lower extensions 255 c may besymmetrically disposed.

FIG. 13 is a plan view of a light emitting diode according to a twelfthexemplary embodiment of the present invention.

Referring to FIG. 13, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIG. 11. In the light emitting diode of the presentexemplary embodiment, however, positions of first electrode pads 265 aredifferent from those of the above exemplary embodiment.

Specifically, the first electrode pads 265 are located in regionsbetween the center and one end on the other edge of the substrate 21.Each of the first electrode pads 265 may be located at a central regionof an edge of a light emitting region LE1 or LE2. Further, each of thefirst electrode pads 265 may be located along an imaginary line formedby extension of each upper extension 253 a. Thus, each of the upperextensions 253 a may be located at the middle between the lowerextension 255 b and the lower extension 255 a, thereby allowing uniformcurrent spreading at both regions of the upper extension 253 a.

In the tenth and eleventh exemplary embodiments, a second electrode pad253 is located on a first conductive type semiconductor layer 23, and aninsulation layer 31 is disposed between the second electrode pad 253 andthe first conductive type semiconductor layer 23. However, as describedabove with reference to FIGS. 5 and 6, the second electrode pad 253 maybe directly located on the substrate 21 to be in contact with thesubstrate 21. Alternatively, the insulation layer 31 may be disposedbetween the substrate 21 and the second electrode pad 253. That is, withthe insulation layer 31 directly located on the substrate 21, the secondelectrode pad 253 may be directly located on the insulation layer 31 tobe in contact with the insulation layer 31. The second electrode pad 253is formed on a region from which the first conductive type semiconductorlayer 23, active layer 25 and second conductive type semiconductor layer27 formed on the substrate 21 have been partially removed. When thesecond electrode pad 253 is directly formed on the substrate 21 to be incontact with the substrate 21, the substrate 21 may be a dielectricsubstrate.

In the above exemplary embodiments, the second electrode pad 253 ishorizontally separated from the second conductive type semiconductorlayer 27. Consequently, it is possible to prevent current crowdingaround the second electrode pad 253. In addition, the second electrodepad 253 is electrically connected to the upper extension 253 a, 253 cthrough the connector 253 b, which is insulated from the light emittingregions by the insulation layer 31. This is similar to the exemplaryembodiment shown in FIGS. 1 and 2. Since the connector 253 b is alsoinsulated from the second conductive type semiconductor layer 27 by theinsulation layer 31, it is possible to prevent current crowding aroundthe second electrode pad 253.

FIG. 14 is a plan view of a light emitting diode according to athirteenth exemplary embodiment of the present invention, and FIGS. 15a,15b and 15c are cross-sectional views taken along lines A-A, B-B and C-Cof FIG. 14, respectively.

Referring to FIGS. 14, 15 a, 15 b and 15 c, the light emitting diodeincludes a substrate 21, a first conductive type semiconductor layer 23,an active layer 25, a second conductive type semiconductor layer 27, aninsulation layer 331, first and second electrode pads 335, 333, andupper extensions 333 a. The light emitting diode may further includeconnectors 333 b, a transparent electrode layer 29, a first lowerextension 335 a, and a second lower extension 335 b.

The substrate 21, first conductive type semiconductor layer 23, activelayer 25, and second conductive type semiconductor layer 27 are the sameas those shown in FIGS. 1 and 2, and a detailed description thereof willbe omitted herein.

The second conductive type semiconductor layer 27 and the active layer25 may be subjected to mesa-etching to expose a region(s) of the firstconductive type semiconductor layer 23, that is, an n-type semiconductorlayer, where the first electrode pad 335, first lower extension 335 aand second extension 335 b will be formed. Mesa-etching may form anindented portion 30 b, so that the second conductive type semiconductorlayer 27 and the active layer 25 are substantially divided into twolight emitting regions. Further, the mesa-etching may be performed toform inclined side surfaces which have a degree of inclination in therange of 30-70 degrees relative to a plane of the substrate 21.

A transparent electrode layer 329 may be formed on the second conductivetype semiconductor layer 27. The transparent electrode layer 329 may beformed of ITO or Ni/Au and forms an ohmic contact with the secondconductive type semiconductor layer 27. For example, as shown in FIG.17b , the transparent electrode layer 329 may be divided into tworegions. Here, the transparent electrode layer 329 may be divided intothe two regions to expose the second conductive type semiconductor layer27 on which the second electrode pad 333 will be formed, and these tworegions may be symmetrically disposed.

The insulation layer 331 covers the second conductive type semiconductorlayer 27. When the transparent electrode layer 329 is located on thesecond conductive type semiconductor layer 27, the insulation layer 331also covers the transparent electrode layer 329. The insulation layer331 also covers side surfaces of the second conductive typesemiconductor layer 27 and active layer 25, which are exposed bymesa-etching. In addition, the insulation layer 331 may have openings331 a formed on the second conductive type semiconductor layer 27. Theopenings 331 a expose the second conductive type semiconductor layer 27(or the transparent electrode layer 329). The insulation layer 331 maybe formed of any transparent material, for example SiO₂, through whichlight can be transmitted.

The second electrode pad 333 is located on the second conductive typesemiconductor layer 27. The second electrode pad 333 is located on aregion of the second conductive type semiconductor layer 27 which isexposed by dividing the transparent electrode layer 329, and isinsulated from the second conductive type semiconductor layer 27 by theinsulation layer 331.

The upper extensions 333 a are located on the second conductive typesemiconductor layer 27 (or the transparent electrode layer 329). Theupper extensions 333 a may be connected to the second conductive typesemiconductor layer 27 (or the transparent electrode layer 329) via theopenings 331 a of the insulation layer 331. The upper extensions 333 aare disposed to allow uniform current spreading in the second conductivetype semiconductor layer 27. For example, the upper extensions 333 a mayextend parallel to each other. The upper extensions 333 a may beconnected to the second electrode pad 333 via the connectors 333 b,respectively. The connectors 333 b are separated from the secondconductive type semiconductor layer 27 by the insulation layer 331.

The first electrode pad 335 is located on the region of the firstconductive type semiconductor layer 23 exposed by mesa-etching. Thefirst electrode pad 335 is electrically connected to the firstconductive type semiconductor layer 23. The first and second electrodepads 335, 333 are bonding pads for wire bonding and have a relativelywide area for wire bonding. The first lower extension 335 a may extendfrom the first electrode pad 335 towards the second electrode pad 333.The first lower extension 335 a is located on the first conductive typesemiconductor layer 23 and is electrically connected thereto. As shownin the figures, the first lower extension 335 a may be located in aregion between the divided regions of the transparent electrode layer329 and parallel to the upper extensions 333 a. In addition, the secondlower extensions 335 b may extend from the first electrode pad 335 alongan edge of the substrate 21.

The electrode pads 333, 335, upper extensions 333 a, connectors 333 b,and lower extension 335 a may be formed of, but are not limited to, thesame material, for example Cr/Au, by the same process. Alternatively,the upper extensions 333 a and the second electrode pad 333 may beformed of different materials by different processes.

In the present exemplary embodiment, the light emitting diode has asymmetrical structure relative to a line crossing the first electrodepad 335 and the second electrode pad 333, for example line B-B of FIG.14. The divided regions of the transparent electrode layer 329 and theupper extensions 333 a are symmetrically disposed. The lower extensions335 b may also be symmetrically disposed. Accordingly, in the lightemitting diode according to the present exemplary embodiment, thedivided regions of the transparent electrode layer 329 may provide thesame luminescence characteristics at both divided regions thereof. As aresult, the light emitting structure of the light emitting diode issubstantially divided into two light emitting regions, so that the lightemitting diode can prevent excessive current crowding around a defectsuch as pin holes or thread dislocations, thereby achieving uniformcurrent spreading.

In the present exemplary embodiment, the first electrode pad 335 islocated on the first conductive type semiconductor layer 23. However, ifthe substrate 21 is conductive, the first electrode pad 335 may belocated on the top or bottom surface of the substrate 21.

FIG. 16 is a cross-sectional view of a light emitting diode according toa fourteenth exemplary embodiment of the present invention.

Referring to FIG. 16, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIGS. 14 and 15. In the light emitting diode of the presentexemplary embodiment, however, an additional portion of a secondelectrode pad 343 is located above a transparent electrode layer 329.

Specifically, the second electrode pad 343 is located above an exposedregion of the second conductive type semiconductor layer 27 between thedivided regions of the transparent electrode layer 329 such that thatportion of the second electrode pad 343 is located above the transparentelectrode layer 329. The second electrode pad 343 is insulated from thetransparent electrode layers 329 by an insulation layer 31.

In the present exemplary embodiment, an area of the region, whichdivides the transparent electrode region 329, may be relativelydecreased. Further, the second electrode pad 343 may be formed to have agreater area than the second electrode pad 333 of the above exemplaryembodiment.

FIGS. 17a, 17b, 17c and 17d are plan views illustrating a method ofmanufacturing a light emitting diode according to the thirteenthexemplary embodiment. Methods of forming semiconductor layers 23, 25,27, a transparent electrode layer 329 and an insulation layer 331 arewell known in the art and a detailed description thereof will be omittedherein. Any process, known now or not yet known, that can formsemiconductor layers 23, 25, 27, a transparent electrode layer 329 andan insulation layer 331, can be used to manufacture the light emittingdiode.

First, referring to FIG. 17a , semiconductor layers including a firstconductive type semiconductor layer 23, active layer 25 and secondconductive type semiconductor layer 27 are formed on a substrate 21.Then, the semiconductor layers are subjected to mesa-etching to exposethe first conductive type semiconductor layer 23. The semiconductorlayers may have inclined surfaces, for example, at 30-70 degreesrelative to a substrate plane. Here, a region 30 a to be formed with afirst electrode pad 335, a region 30 b to be formed with a first lowerextension 335 a, and a region 30 c to be formed with a second lowerextension 335 b are exposed on the first conductive type semiconductorlayer 23. The region 30 b to be formed with the first lower extension335 a becomes an indented portion 30 b which extends inwardly. Theindented portion 30 b is located at the middle of the semiconductorlayers and extends inwardly from the region 30 a, on which the firstelectrode pad will be formed, to divide a light emitting region intosubstantially two light emitting regions. Here, a region of the secondconductive type semiconductor layer and active layer to be formed withthe second electrode pad 333 (see FIG. 14) remains instead of beingremoved by etching.

Referring to FIG. 17b , a transparent electrode layer 329 may be formedon the second conductive type semiconductor layer 27. The transparentelectrode layer 329 may be divided into the two regions to expose thesecond conductive type semiconductor layer 27 on which the secondelectrode pad 333 will be formed. The two regions of the transparentelectrode layer 329 may have a symmetrical structure relative to eachother. The transparent electrode layer 329 may be formed of ITO or Ni/Auand forms an ohmic contact with the second conductive type semiconductorlayer 27.

Referring to FIG. 17c , an insulation layer 331 is formed on thetransparent electrode layer 329. The insulation layer 331 covers aregion of the second conductive type semiconductor layer 27 on which thesecond electrode pad 333 will be formed. Further, the insulation layer331 may also cover side surfaces of the second conductive typesemiconductor layer 27 and active layer 25, which are exposed bymesa-etching. In addition, the insulation layer 331 is subjected to apatterning process to form openings 331 a, which expose the transparentelectrode layer 329, via photolithography and etching. The openings 331a exposing the transparent electrode layer 329 may be symmetricallyformed parallel to each other. Further, the regions 30 a, 30 b, 30 c ofthe first conductive type semiconductor layer, on which the firstelectrode pad 335, first lower extension 335 a and second extension 335b will be respectively formed, are also exposed therethrough.

Referring to FIG. 17d , the first electrode pad 335, first lowerextension 335 a and second extension 335 b are formed on the exposedregions of the first conductive type semiconductor layer 23. Further, asecond electrode pad 333 and connectors 333 b are formed on theinsulation layer 331, and upper extensions 333 a are formed in theopenings 331 a.

The upper extensions 333 a may be connected to the transparent electrodelayer 329 and be formed parallel to the first lower extension 335 a. Asa result, a light emitting diode is fabricated, as shown in FIG. 14.

In the present exemplary embodiment, the transparent electrode layer 329is divided into the two regions, but is not limited thereto. Thetransparent electrode layer 329 may be divided into more than tworegions. Further, although the transparent electrode layer 329 is formedafter mesa-etching in the present exemplary embodiment, the mesa-etchingmay be carried out after formation of the transparent electrode layer329.

FIG. 18 is a plan view of a light emitting diode according to afifteenth exemplary embodiment of the present invention.

In the above exemplary embodiment of FIG. 14, the first and secondelectrode pads 335, 333 are disposed in a major axis direction of thelight emitting diode, and the transparent electrode layer 329 is dividedinto the two regions in the major axis direction of the light emittingdiode. In the present exemplary embodiment, however, the first andsecond electrode pads 335, 333 are disposed in a minor axis direction ofthe light emitting diode, and the transparent electrode layer 329 isdivided into the two regions in the minor axis direction of the lightemitting diode. Further, the divided regions of the transparentelectrode layer 329 are symmetrically disposed, and the upper extensions353 a and lower extensions 355 a are also symmetrically disposed.

Here, the upper extensions 353 a extend along an edge of the lightemitting diode to surround the light emitting diode and includeextensions 353 c extending inwardly from the edge of the light emittingdiode. The lower extensions 355 a extend outwardly from the interior ofthe light emitting diode. Further, the lower extensions 355 a may bebifurcated to surround the extensions 353 c in associated light emittingregions, respectively.

The upper extensions 353 a are connected to the transparent electrodelayer 329 through the openings 331 a of the insulation layer 331, andconnected to the second electrode pad 353 through the connectors 353 b.The connectors 353 b are insulated from the transparent electrode layer329 by the insulation layer 331.

In the present exemplary embodiment, the light emitting diode omits thefirst lower extension 335 a (see FIG. 14), which extends from the firstelectrode pad 355 towards the second electrode pad 353.

FIG. 19 is a plan view of a light emitting diode according to asixteenth exemplary embodiment of the present invention.

Referring to FIG. 19, the light emitting diode of the present exemplaryembodiment is similar to the light emitting diode described withreference to FIG. 18. In the light emitting diode of the presentexemplary embodiment, however, lower extensions 365 a and upperextensions 363 a are arranged in a different manner than in the aboveexemplary embodiment.

Specifically, the lower extensions 365 a extend along an edge of thelight emitting diode and are bent to extend inwardly, and the upperextensions 363 a include two extensions on each of divided regions ofthe transparent electrode layer 329, which surround each of the lowerextensions 365 a extending inwardly.

The upper extensions 363 a are connected to the transparent electrodelayer 329 through openings 331 a of an insulation layer 331, and areconnected to a second electrode pad 353 through connectors 363 b. Theconnectors 363 b are insulated from the transparent electrode layer 329by the insulation layer 331.

FIG. 20 is a plan view of a light emitting diode according to aseventeenth exemplary embodiment of the present invention, and FIGS.21a, 21b and 21c are cross-sectional views taken along lines A-A, B-Band C-C of FIG. 20, respectively.

Referring to FIGS. 20, 21 a, 21 b and 21 c, the light emitting diode ofthe present exemplary embodiment is similar to the light emitting diodedescribed with reference to FIGS. 14 and 15. In the light emitting diodeof the present exemplary embodiment, however, a second electrode pad 433is located above a transparent electrode layer 429 and insulatedtherefrom by an insulation layer 431. Further, a first conductive typesemiconductor layer 23 is an n-type semiconductor layer and a secondconductive type semiconductor layer 27 is a p-type semiconductor layer.

The light emitting diode includes a substrate 21, an n-typesemiconductor layer 23, an active layer 25, a p-type semiconductor layer27, the transparent electrode layer 429, the insulation layer 431, firstand second electrode pads 435, 433, and upper extensions 433 a. Thelight emitting diode may further include connectors 433 b, a first lowerextension 435 a, and a second lower extension 435 b.

The substrate 21, n-type semiconductor layer 23, active layer 25, andp-type semiconductor layer 27 are the same as those shown in FIGS. 14and 15, and a detailed description thereof will be omitted herein.

The transparent electrode layer 429 may be located on the p-typesemiconductor layer 27. The transparent electrode layer 429 may beformed of ITO or Ni/Au and forms an ohmic contact with the p-typesemiconductor layer 27. For example, as shown in FIG. 22b , thetransparent electrode layer 429 may be formed on the p-typesemiconductor layer 27 and have a symmetrical structure. Here, thetransparent electrode layer 429 covers a region of the p-typesemiconductor layer 27 on which the second electrode pad 433 will beformed.

The insulation layer 431 covers the transparent electrode layer 429. Theinsulation layer 431 also covers side surfaces of the p-typesemiconductor layer 27 and active layer 25, which are exposed bymesa-etching. In addition, the insulation layer 431 may have openings431 a exposing the transparent electrode layer 429. The transparentelectrode layer 429 (or the p-type semiconductor layer 27) is exposedthrough the openings 431 a. The insulation layer 431 may be formed ofany transparent material, for example SiO₂, through which light can betransmitted.

The second electrode pad 433 is located on the transparent electrodelayer 429. The second electrode pad 433 is located on a region of thetransparent electrode layer 429 near an indented portion 30 b and isinsulated from the transparent electrode layer 429 by the insulationlayer 431.

The upper extensions 433 a are located on the transparent electrodelayer 429. The upper extensions 433 a may be connected to thetransparent electrode layer 429 via the openings 431 a of the insulationlayer 431, and may thus be electrically connected to the p-typesemiconductor layer 27. The p-type semiconductor layer 27 may be exposedthrough the openings 431 a, and the upper extensions 433 a may bedirectly connected to the p-type semiconductor layer 27. The upperextensions 433 a are disposed to allow uniform current spreading in thep-type semiconductor layer 27. For example, the upper extensions 433 amay extend parallel to each other. The upper extensions 433 a may beconnected to the second electrode pad 433 via the connectors 433 b,respectively. The connectors 433 b are insulated from the transparentelectrode layer 429 by the insulation layer 431.

The first electrode pad 435 may be located on the region of the n-typesemiconductor layer 23 exposed by mesa-etching. The first electrode pad435 is electrically connected to the n-type semiconductor layer 23. Thefirst and second electrode pads 435, 433 are bonding pads for wirebonding and may have a relatively wide area for wire bonding. The firstlower extension 435 a may extend from the first electrode pad 435towards the second electrode pad 433. The first lower extension 435 a islocated on the n-type semiconductor layer 23 and is electricallyconnected thereto. As shown in the figures, the first lower extension435 a may be located in the indented portion 30 b and parallel to theupper extensions 433 a. In addition, the second lower extensions 435 bmay extend from the first electrode pad 435 along an edge of thesubstrate 21.

The electrode pads 433, 435, upper extensions 433 a, connectors 433 b,and first and second lower extensions 435 a, 435 b may be formed of, butare not limited to, the same material, for example Cr/Au, by the sameprocess. Alternatively, the upper extensions 433 a and the secondelectrode pad 433 may be formed of different materials by differentprocesses.

In the present exemplary embodiment, the light emitting diode has asymmetrical structure relative to a line crossing the first electrodepad 435 and the second electrode pad 433, for example line B-B of FIG.20. The divided regions of the transparent electrode layer 429 and theupper extensions 433 a may be symmetrically disposed, and the secondlower extensions 435 b may also be symmetrically disposed. Accordingly,the light emitting diode may exhibit the same luminescencecharacteristics at both sides of the indented portion 30 b. As a result,the light emitting structure of the light emitting diode issubstantially divided into two light emitting regions, so that the lightemitting diode can prevent excessive current crowding around a defectsuch as pin holes or thread dislocations, thereby achieving uniformcurrent spreading.

In the present exemplary embodiment, the first electrode pad 435 islocated on the n-type semiconductor layer 23. However, if the substrate21 is conductive, the first electrode pad 435 may be located on the topor bottom surface of the substrate 21.

FIGS. 22a, 22b, 22c and 22d are plan views illustrating a method ofmanufacturing a light emitting diode according to the seventeenthexemplary embodiment. Methods of forming semiconductor layers 23, 25,27, a transparent electrode layer 429 and an insulation layer 431 arewell known in the art and a detailed description thereof will be omittedherein. Any process, known now or not yet known, that can formsemiconductor layers 23, 25, 27, a transparent electrode layer 329 andan insulation layer 331, can be used to manufacture the light emittingdiode.

First, referring to FIG. 22a , semiconductor layers including an n-typesemiconductor layer 23, active layer 25 and p-type semiconductor layer27 are formed on a substrate 21. Then, the semiconductor layers aresubjected to mesa-etching to expose the n-type semiconductor layer 23.The semiconductor layers may have inclined surfaces, for example, at30-70 degrees relative to a substrate plane. Here, a region 30 a to beformed with a first electrode pad 435, a region 30 b to be formed with afirst lower extension 435 a, and a region 30 c to be formed with asecond lower extension 435 b are exposed on the n-type semiconductorlayer 23. The region 30 b to be formed with the first lower extension435 a becomes an indented portion 30 b which extends inwardly. Theindented portion 30 b extends inwardly from the region 30 a, on whichthe first electrode pad will be formed, to divide a light emittingregion into substantially two light emitting regions. Here, a region ofthe p-type semiconductor layer and active layer to be formed with thesecond electrode pad 433 (see FIG. 20) remains instead of being removedby etching.

Referring to FIG. 22b , a transparent electrode layer 429 may be formedon the p-type semiconductor layer 27. The transparent electrode layer429 may be formed to cover the p-type semiconductor layer 27 on whichthe second electrode pad 333 will be formed, and may be divided into tworegions disposed in a symmetrical structure relative to a line extendingalong the indented portion 30 c. The transparent electrode layer 429 maybe formed of ITO or Ni/Au and forms an ohmic contact with the p-typesemiconductor layer 27.

Referring to FIG. 22c , an insulation layer 431 is formed on thetransparent electrode layer 429. The insulation layer 431 covers aregion of the transparent electrode layer 429 on which the secondelectrode pad 433 will be formed. Further, the insulation layer 431 mayalso cover side surfaces of the p-type semiconductor layer 27 and activelayer 25, which are exposed by mesa-etching. In addition, the insulationlayer 431 is subjected to a patterning process to form openings 431 a,which expose the transparent electrode layer 429, via photolithographyand etching. The openings 431 a exposing the transparent electrode layer429 may be symmetrically formed parallel to each other. Further, theregions of the n-type semiconductor layer 23, on which the firstelectrode pad 435, first lower extension 435 a and second extension 435b will be respectively formed, are also exposed therethrough.

Referring to FIG. 22d , the first electrode pad 435, first lowerextension 435 a and second extension 435 b are formed on the exposedregions of the n-type semiconductor layer 23. Further, a secondelectrode pad 433 and connectors 433 b are formed on the insulationlayer 431, and upper extensions 433 a are formed in the openings 431 a.

The upper extensions 433 a may be connected to the transparent electrodelayer 429 and be formed parallel to the first lower extension 435 a. Asa result, a light emitting diode is fabricated, as shown in FIG. 20.

In the present exemplary embodiment, the light emitting structure issubstantially divided into the two light emitting regions by theindented portion 30 b, but is not limited thereto. The light emittingstructure may be divided into more than two light emitting regions.Further, although the transparent electrode layer 429 is formed aftermesa-etching in the present exemplary embodiment, the mesa-etching maybe carried out after formation of the transparent electrode layer 429.

Unlike the light emitting diode of the thirteenth exemplary embodiment,the light emitting diode of the present exemplary embodiment includesthe second electrode pad 433 above the transparent electrode layer 429.This feature may also be applied to the light emitting diodes of thefifteenth and sixteenth exemplary embodiments described with referenceto FIGS. 18 and 19, and a detailed description thereof will be omittedherein.

FIG. 23 is a plan view of a light emitting diode according to aneighteenth exemplary embodiment of the present invention, and FIGS. 24a,24b and 24c are cross-sectional views taken along lines A-A, B-B and C-Cof FIG. 23, respectively.

Referring to FIGS. 23, 24 a, 24 b and 24 c, the light emitting diodeincludes a substrate 21, a light emitting structure including lightemitting regions LE1, LE2, an electrode pad region EP isolated from thelight emitting structure, a first electrode pad 535, a second electrodepad 533, and upper extensions 533 a. Further, the light emitting diodemay include a transparent electrode layer 529, an insulation layer 531,connectors 533 b, a first lower extension 535 a, and a second lowerextension 535 b. In addition, each of the light emitting structure andthe electrode pad region EP includes a first conductive typesemiconductor layer 23, an active layer 25, and a second conductive typesemiconductor layer 27.

The substrate 21 may be, for example, a sapphire substrate, but is notlimited thereto. The emitting structure and the electrode pad region EPare located on the substrate 21.

The first conductive type semiconductor layer 23 is an n-typesemiconductor layer and the second conductive type semiconductor layer27 is a p-type semiconductor layer, or vice versa. The first conductivetype semiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 are the same as those described with reference toFIGS. 14 and 15, and a detailed description thereof will be omittedherein.

The second conductive type semiconductor layer 27 and active layer 25 ofthe light emitting structure may be divided to define at least two lightemitting regions LE1, LE2. The light emitting regions LE1, LE2 may havea symmetrical structure and such a dividing process may be carried outby mesa-etching. Specifically, an indented portion 30 b is formed bymesa-etching to divide the second conductive type semiconductor layer 27and active layer 25 into the two light emitting regions. Further, sidesurfaces of the light emitting structure subjected to mesa-etching maybe inclined at 30-70 degrees relative to a substrate plane relative to aplane of the substrate 21. Further, the first conductive typesemiconductor layer 23 of the light emitting regions LE1, LE2 may beshared by the light emitting regions, so that the first conductive typesemiconductor layer 23 is exposed between the light emitting regions.

In addition, a transparent electrode layer 529 may be located on thesecond conductive type semiconductor layer 27 of the light emittingstructure. The transparent electrode layer 529 may be formed of ITO orNi/Au and forms an ohmic contact with the second conductive typesemiconductor layer 27.

The electrode pad region EP is isolated from the light emittingstructure. Specifically, the first conductive type semiconductor layer23, active layer 25 and second conductive type semiconductor layer 27 ofthe electrode pad region EP are separated from the first conductive typesemiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 of the light emitting structure. Accordingly, theelectrode pad region EP is electrically insulated from the lightemitting structure. The electrode pad region EP may be isolated from thelight emitting structure by a trench TI formed in the first conductivetype semiconductor layer 23. On the other hand, the transparentelectrode layer 529 formed of ITO or Ni/Au may be located on theelectrode pad region EP.

An insulation layer 531 may cover the second conductive typesemiconductor layer 27 (or the transparent electrode layer 529) of thelight emitting structure. The insulation layer 531 may also cover sidesurfaces of the second conductive type semiconductor layer 27 and activelayer 25, which are exposed by mesa-etching. In addition, the insulationlayer 531 may have openings 431 a which expose the transparent electrodelayer 529 on the light emitting regions LE1, LE2. The transparentelectrode layer 529 (or the second conductive type semiconductor layer27) is exposed through the openings 531 a. The insulation layer 531 maycover the second conductive type semiconductor layer 27 (or thetransparent electrode layer 529) of the electrode pad region EP, andalso cover a side surface of the electrode pad region EP. The insulationlayer 531 may be formed of any transparent material, for example SiO₂,through which light can be transmitted.

The first electrode pad 535 may be located on an exposed region of thefirst conductive type semiconductor layer 23 of the light emittingstructure, and the second electrode pad 533 may be located on theelectrode pad region EP. The first electrode pad 535 may be located toface the second electrode pad 533, as shown in the figures. The firstand second electrode pads 535, 533 are bonding pads for wire bonding andmay have a relatively wide area for wire bonding.

The first electrode pad 535 is electrically connected to the firstconductive type semiconductor layer 23. Further, the first lowerextension 535 a may extend from the first electrode pad 535 towards thesecond electrode pad 533. The first lower extension 535 a is located onthe first conductive type semiconductor layer 23 and electricallyconnected thereto. As shown in the figures, the first lower extension535 a may be located in the indented portion 30 b between the lightemitting regions LE1, LE2 and has a distal end near the second electrodepad 533. In addition, the second lower extensions 535 b may extend fromthe first electrode pad 535 along an edge of the substrate 21.

The second electrode pad 533 is located on the electrode pad region EP.The second electrode pad 533 may be located on the second conductivetype semiconductor layer 27 and the transparent electrode layer 529and/or the insulation layer 531 may be disposed between the secondelectrode pad 533 and the second conductive type semiconductor layer 27.When the insulation layer 531 is disposed between the second electrodepad 533 and the second conductive type semiconductor layer 27 (or thetransparent electrode layer 529), the second electrode pad may beinsulated from the electrode pad region EP.

The upper extensions 533 a are located on the light emitting regionsLE1, LE2. The upper extensions 533 a may be electrically connected tothe transparent electrode layer 529 (or the second conductive typesemiconductor layer 27) via the openings 531 a of the insulation layer531. The second conductive type semiconductor layer 27 may be exposedthrough the openings 531 a, and the upper extensions 533 a may bedirectly connected to the second conductive type semiconductor layer 27.The upper extensions 533 a are disposed to allow uniform currentspreading in the second conductive type semiconductor layer 27. Forexample, the upper extensions 533 a may extend parallel to each other.The upper extensions 533 a may be connected to the second electrode pad533 via connectors 533 b, respectively. The connectors 533 b areinsulated from the transparent electrode layer 529 (or the secondconductive type semiconductor layer 27) by the insulation layer 531. Theconnectors 533 b are insulated from the side surface of the lightemitting structure by the insulation layer 531.

The electrode pads 533, 535, upper extensions 533 a, connectors 533 b,and first and second lower extensions 535 a, 535 b may be formed of, butare not limited to, the same material, for example Cr/Au, by the sameprocess. Alternatively, the upper extensions 433 a and the secondelectrode pad 433 may be formed of different materials by differentprocesses.

In the present exemplary embodiment, the light emitting diode has asymmetrical structure relative to a line crossing the first electrodepad 535 and the second electrode pad 533, for example line B-B of FIG.23. The divided regions of the transparent electrode layer 529 and theupper extensions 533 a may be symmetrically disposed, and the secondlower extensions 535 b may also be symmetrically disposed. Accordingly,the light emitting diode may exhibit the same luminescencecharacteristics at both sides of the indented portion 30 b. As a result,the light emitting structure of the light emitting diode is divided intotwo light emitting regions, so the light emitting diode can preventexcessive current crowding around a defect such as pin holes or threaddislocations, thereby achieving uniform current spreading.

In the present exemplary embodiment, the first electrode pad 535 islocated on the first conductive type semiconductor layer 23. However, ifthe substrate 21 is conductive, the first electrode pad 535 may belocated on the top or bottom surface of the substrate 21. In this case,the second electrode pad 533 is insulated from the electrode pad regionEP by the insulation layer 531.

FIGS. 25a, 25b, 25c, 25d and 25e are plan views illustrating a method ofmanufacturing a light emitting diode according to the eighteenthexemplary embodiment. A method of forming semiconductor layers 23, 25,27, a transparent electrode layer 529 and an insulation layer 531 iswell known in the art and a detailed description thereof will be omittedherein.

First, referring to FIG. 25a , semiconductor layers including an n-typesemiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 are formed on a substrate 21. Then, thesemiconductor layers are subjected to mesa-etching to expose the firstconductive type semiconductor layer 23. The semiconductor layers mayhave inclined surfaces, for example, at 30-70 degrees relative to asubstrate plane. Here, as shown in FIG. 23, a region 30 a to be formedwith a first electrode pad 535, a region 30 b to be formed with a firstlower extension 535 a, and a region 30 c to be formed with a secondlower extension 535 b are exposed on the first conductive typesemiconductor layer 23. The region 30 b to be formed with the firstlower extension 535 a becomes an indented portion 30 b which extendsinwardly. The indented portion 30 b extends inwardly from the region 30a, on which the first electrode pad will be formed. Here, the firstconductive type semiconductor layer 23 in the electrode pad region EP isexposed by mesa-etching, and the second conductive type semiconductorlayer 27 and active layer 23 remain instead of being removed by etching.Accordingly, the second conductive type semiconductor layer 27 andactive layer 23 are divided to define two light emitting regions LE1,LE2 and the electrode pad region EP is defined by the mesa-etching.

Referring to FIG. 25b , a trench TI is formed around the electrode padregion EP by etching the first conductive type semiconductor layer 23.The electrode pad region EP is isolated in an island shape from thefirst conductive type semiconductor layer 23 of the light emittingstructure, which includes the light emitting regions LE1, LE2, by thetrench TI.

Referring to FIG. 25c , a transparent electrode layer 529 may be formedon the second conductive type semiconductor layer 27 of the lightemitting regions LE1, LE2. The transparent electrode layer 529 may alsobe formed on the electrode pad region EP. The transparent electrodelayer 529 may have a symmetrical structure relative to an imaginary lineextending along the indented portion 30 c. The transparent electrodelayer 529 may be formed of ITO or Ni/Au and forms an ohmic contact withthe second conductive type semiconductor layer 27.

Referring to FIG. 25d , an insulation layer 531 is formed on the lightemitting structure. The insulation layer 531 covers the transparentelectrode layer 529 of the light emitting structure and the transparentelectrode layer 529 on the electrode pad region EP. Further, theinsulation layer 531 may also cover side surfaces of the secondconductive type semiconductor layer 27 and active layer 25, which areexposed by mesa-etching. In addition, the insulation layer 531 issubjected to a patterning process to form openings 531 a, which exposethe transparent electrode layer 529 on light emitting regions LE1, LE2,via photolithography and etching. The openings 531 a exposing thetransparent electrode layer 529 may be symmetrically formed parallel toeach other. Further, the regions of the first conductive typesemiconductor layer 23, on which the first electrode pad 535, firstlower extension 535 a and second extension 535 b will be respectivelyformed, are also exposed therethrough.

Referring to FIG. 25e , the first electrode pad 535, first lowerextension 535 a and second extension 535 b are formed on the exposedregions of the first conductive type semiconductor layer 23 of the lightemitting structure. Further, a second electrode pad 533 is formed on theelectrode pad region EP, and upper extensions 533 a are formed in theopenings 531 a. Further, connectors 533 b are formed to connect thesecond electrode pad 533 to the upper extensions 533 a.

The upper extensions 533 a may be connected to the transparent electrodelayer 529 and be formed parallel to the first lower extension 535 a. Asa result, a light emitting diode is fabricated as shown in FIG. 23.

In the present exemplary embodiment, the light emitting structure isdivided into the two light emitting regions LE1, LE2, but is not limitedthereto. The light emitting structure may be divided into more than twolight emitting regions. Further, although the transparent electrodelayer 529 is formed after mesa-etching in the present exemplaryembodiment, the mesa-etching may be carried out after formation of thetransparent electrode layer 529. Moreover, although the trench TI isformed after mesa-etching in the present exemplary embodiment, themesa-etching may be carried out after formation of the trench TI.

FIG. 26 is a plan view of a light emitting diode according to anineteenth exemplary embodiment of the present invention.

In the above exemplary embodiment of FIG. 23, the first and secondelectrode pads 535, 533 are disposed in a major axis direction of thelight emitting diode, and the indented portion 30 b is formed in themajor axis direction of the light emitting diode. In the presentexemplary embodiment, however, the first and second electrode pads 535,533 are disposed in a minor axis direction of the light emitting diode,and an indented portion 560 b is formed in the minor axis direction ofthe light emitting diode. Further, the transparent electrode layers 529,upper extensions 553 a and lower extensions 555 a are also symmetricallydisposed.

Here, the upper extensions 553 a extend along an edge of the lightemitting diode to surround the light emitting diode and includeextensions 553 b extending inwardly from the edge of the light emittingdiode. Lower extensions 555 a extend outwardly from the interior of thelight emitting diode. Further, the lower extensions 555 a may bebifurcated to surround the extensions 553 b in associated light emittingregions, respectively.

The upper extensions 553 a are connected to the transparent electrodelayer 529 on the light emitting regions LE1, LE2 through openings 531 aof the insulation layer 531, and connected to the second electrode pad553 through the connectors 553 b. The connectors 553 b are insulatedfrom the transparent electrode layer 529 by the insulation layer 531.

As described with reference to FIG. 23, the electrode pad region EP isisolated from the light emitting structure by the trench TI.

In the present exemplary embodiment, the light emitting diode omits thefirst lower extension 535 a (see FIG. 23), which extends from the firstelectrode pad 555 towards the second electrode pad 553.

FIG. 27 is a plan view of a light emitting diode according to atwentieth exemplary embodiment of the present invention.

Referring to FIG. 27, the light emitting diode of the present exemplaryembodiment is generally similar to the light emitting diode describedwith reference to FIG. 26. In the light emitting diode of the presentexemplary embodiment, however, lower extensions 565 a and upperextensions 563 a are arranged in a different manner than in the aboveexemplary embodiment.

Specifically, the lower extensions 565 a extend along an edge of thelight emitting diode and are bent to extend inwardly, and the upperextensions 563 a include two extensions on each of divided regions ofthe transparent electrode layer 529, which surround each of the lowerextensions 565 a extending inwardly.

The upper extensions 563 a are connected to the transparent electrodelayer 529 on light emitting regions LE1, LE2 through openings 531 a ofan insulation layer 531, and are connected to the second electrode pad553 through connectors 563 b. The connectors 563 b are insulated fromthe light emitting structure by the insulation layer 531

FIG. 28 is a plan view of a light emitting diode according to atwenty-first exemplary embodiment of the present invention, and FIGS.29a, 29b and 29c are cross-sectional views taken along lines A-A, B-Band C-C of FIG. 28, respectively.

Referring to FIGS. 28, 29 a, 29 b and 29 c, the light emitting diode ofthe present exemplary embodiment is generally similar to the lightemitting diode described with reference to FIGS. 23 and 24. In the lightemitting diode of the present exemplary embodiment, however, a secondelectrode pad 633 is located on an isolated electrode pad region EP of afirst conductive type semiconductor layer 23. The same components asthose of the above exemplary embodiments will be omitted for clarity.

In the present exemplary embodiment, a light emitting structure and theelectrode pad region EP are located on the substrate 21, and theelectrode pad region EP includes the first conductive type semiconductorlayer 23.

The electrode pad region EP is isolated from the light emittingstructure. Specifically, the first conductive type semiconductor layer23 in the electrode pad region EP is separated from the first conductivetype semiconductor layer 23 of the light emitting structure.Accordingly, the electrode pad region EP is electrically insulated fromthe light emitting structure. The electrode pad region EP may beisolated from the light emitting structure by a trench TI formed in thefirst conductive type semiconductor layer 23 in the electrode pad regionEP. An insulation layer 531 may cover the first conductive typesemiconductor layer 23 of the electrode pad region EP and may also coverthe electrode pad region EP.

A second electrode pad 633 is located on the electrode pad region EP.The second electrode pad 633 may be located on the first conductive typesemiconductor layer 23 and the insulation layer 531 may be disposedbetween the second electrode pad 633 and the first conductive typesemiconductor layer 23. When the insulation layer 531 is disposedbetween the second electrode pad 633 and the first conductive typesemiconductor layer 23, the second electrode pad may be electricallyinsulated from the electrode pad region EP.

FIGS. 30a, 30b, 30c, 30d and 30e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-firstexemplary embodiment. Methods of forming semiconductor layers 23, 25,27, a transparent electrode layer 29 and an insulation layer 31 are wellknown in the art and a detailed description thereof will be omittedherein. Any process, known now or not yet known, that can formsemiconductor layers 23, 25, 27, a transparent electrode layer 329 andan insulation layer 331, can be used to manufacture the light emittingdiode.

First, referring to FIG. 30a , semiconductor layers including an n-typesemiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 are formed on a substrate 21. Then, thesemiconductor layers are subjected to mesa-etching to expose the firstconductive type semiconductor layer 23. The semiconductor layers mayhave inclined surfaces, for example, at 30-70 degrees relative to asubstrate plane. Here, as shown in FIG. 28, a region 30 a to be formedwith a first electrode pad 535, a region 30 b to be formed with a firstlower extension 535 a, and a region 30 c to be formed with a secondlower extension 535 b are exposed on the first conductive typesemiconductor layer 23. The region 30 b to be formed with the firstlower extension 535 a becomes an indented portion 30 b which extendsinwardly. The indented portion 30 b extends inwardly from the region 30a, on which the first electrode pad will be formed. Here, the firstconductive type semiconductor layer 23 of the electrode pad region EP isexposed by mesa-etching. Accordingly, the second conductive typesemiconductor layer 27 and active layer 23 are divided to define twolight emitting regions LE1, LE2 by the mesa-etching.

Referring to FIG. 30b , a trench TI is formed around the electrode padregion EP by etching the first conductive type semiconductor layer 23.The electrode pad region EP is isolated in an island shape from thefirst conductive type semiconductor layer 23 of the light emittingstructure, which includes the light emitting regions LE1, LE2, by thetrench TI.

Referring to FIG. 30c , a transparent electrode layer 529 may be formedon the second conductive type semiconductor layer 27 of the lightemitting regions LE1, LE2. The transparent electrode layer 529 may havea symmetrical structure relative to an imaginary line extending alongthe indented portion 30 c. The transparent electrode layer 529 may beformed of ITO or Ni/Au and forms an ohmic contact with the secondconductive type semiconductor layer 27.

Referring to FIG. 30d , an insulation layer 531 is formed on the lightemitting structure. The insulation layer 531 covers the transparentelectrode layer 529 of the light emitting structure and the firstconductive type semiconductor layer 23 on the electrode pad region EP.The insulation layer 531 may also cover side surfaces of the secondconductive type semiconductor layer 27 and active layer 25, which areexposed by mesa-etching. In addition, the insulation layer 531 issubjected to a patterning process to form openings 531 a, which exposethe transparent electrode layer 529 on light emitting regions LE1, LE2,via photolithography and etching. The openings 531 a exposing thetransparent electrode layer 529 may be symmetrically formed parallel toeach other. Further, the regions 30 a, 30 b, 30 c of the firstconductive type semiconductor layer 23, on which the first electrode pad535, first lower extension 535 a and second extension 535 b will berespectively formed, are also exposed therethrough.

Referring to FIG. 30e , the first electrode pad 535, first lowerextension 535 a and second extension 535 b are formed on the exposedregions of the first conductive type semiconductor layer 23 of the lightemitting structure. Further, a second electrode pad 633 is formed on theelectrode pad region EP, and upper extensions 533 a are formed on theopenings 531 a. Further, connectors 533 b are formed to connect thesecond electrode pad 633 to the upper extensions 533 a.

The upper extensions 533 a may be connected to the transparent electrodelayer 529 and be formed parallel to the first lower extension 535 a. Asa result, a light emitting diode is fabricated as shown in FIG. 28.

As compared with the light emitting diode of the exemplary embodimentshown in FIGS. 24 and 25, the electrode pad region EP of the presentexemplary embodiment isolated from the light emitting structure isformed in the first conductive type semiconductor layer 23. Accordingly,the second electrode pad 633 is located on the first conductive typesemiconductor layer 23 or on the insulation layer 531 of the firstconductive type semiconductor layer. The feature of forming theelectrode pad region EP using the first conductive type semiconductorlayer 23 may also be applied to the light emitting diodes described withreference to FIGS. 26 and 27.

FIG. 31 is a plan view of a light emitting diode according to atwenty-second exemplary embodiment of the present invention, and FIGS.32a, 32b and 32c are cross-sectional views taken along lines A-A, B-Band C-C of FIG. 31, respectively.

Referring to FIGS. 31, 32 a, 32 b and 32 c, the light emitting diode ofthe present exemplary embodiment is similar to the light emitting diodedescribed with reference to FIGS. 23 and 24. In the light emitting diodeof the present exemplary embodiment, however, a second electrode pad 733is located on an electrode pad region EP on a substrate 21. Descriptionof the same components as those described in the above exemplaryembodiments will be omitted.

In the present exemplary embodiment, the substrate 21 is a dielectricsubstrate, such as a sapphire substrate. The second electrode pad 733 islocated on the substrate 21 to be in contact with the substrate 21 andmay be isolated from a light emitting structure. Specifically, thesecond electrode pad 733 is separated from a first conductive typesemiconductor layer 23 of the light emitting structure. The secondelectrode pad 733 is in contact with the substrate 21 through a hole 23a formed by etching the first conductive type semiconductor layer 23.

In the present exemplary embodiment, the second electrode pad 733 isdescribed as being in contact with the substrate 21. Alternatively, aninsulation layer 531 may be disposed between the second electrode pad733 and the substrate 21. In other words, the insulation layer 531 maycover a sidewall and bottom of the hole 23 a. In this case, since thesecond electrode pad 733 is insulated from the substrate by theinsulation layer 31, the substrate 21 may be conductive.

FIGS. 33a, 33b, 33c, 33d and 33e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-secondexemplary embodiment. Methods of forming semiconductor layers 23, 25,27, a transparent electrode layer 29 and an insulation layer 31 are wellknown in the art and a detailed description thereof will be omittedherein. Any process, known now or not yet known, that can formsemiconductor layers 23, 25, 27, a transparent electrode layer 329 andan insulation layer 331, can be used to manufacture the light emittingdiode.

First, referring to FIG. 33a , semiconductor layers including an n-typesemiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 are formed on a substrate 21. Then, thesemiconductor layers are subjected to mesa-etching to expose the firstconductive type semiconductor layer 23. The semiconductor layers mayhave inclined surfaces, for example, at 30-70 degrees relative to asubstrate plane. Here, as shown in FIG. 31, a region 30 a to be formedwith a first electrode pad 535, a region 30 b to be formed with a firstlower extension 535 a, and a region 30 c to be formed with a secondlower extension 535 b are exposed on the first conductive typesemiconductor layer 23. The region 30 b to be formed with the firstlower extension 535 a becomes an indented portion 30 b which extendsinwardly. The indented portion 30 b extends inwardly from the region 30a, on which the first electrode pad will be formed. Here, an upperportion of the electrode pad region EP, on which the second electrodepad will be formed, and the first conductive type semiconductor layer 23around the electrode pad region EP are exposed by mesa-etching.Accordingly, the second conductive type semiconductor layer 27 andactive layer 23 are divided to define two light emitting regions LE1,LE2 by the mesa-etching.

Referring to FIG. 33b , a hole 23 a is formed to expose the substrate 21by etching the first conductive type semiconductor layer 23 in theelectrode pad region EP. The hole 23 a may be formed to have a greaterarea than that of the electrode pad region EP, to encompass theelectrode pad region EP.

Referring to FIG. 33c , a transparent electrode layer 529 may be formedon the second conductive type semiconductor layer 27 of the lightemitting regions LE1, LE2. The transparent electrode layer 529 may havea symmetrical structure relative to an imaginary line extending alongthe indented portion 30 c. The transparent electrode layer 529 may beformed of ITO or Ni/Au and forms an ohmic contact with the secondconductive type semiconductor layer 27.

Referring to FIG. 33d , an insulation layer 531 is formed on the lightemitting structure. The insulation layer 531 covers the transparentelectrode layer 529 of the light emitting structure. The insulationlayer 531 may also cover side surfaces of the second conductive typesemiconductor layer 27 and active layer 25, which are exposed bymesa-etching, and may cover a sidewall of the hole 23 a. In addition,the insulation layer 531 is subjected to a patterning process to formopenings 531 a, which expose the transparent electrode layer 529 onlight emitting regions LE1, LE2, via photolithography and etching. Theopenings 531 a exposing the transparent electrode layer 529 may besymmetrically formed parallel to each other. Further, the regions 30 a,30 b, 30 c of the first conductive type semiconductor layer 23, on whichthe first electrode pad 535, first lower extension 535 a and secondextension 535 b will be respectively formed, are also exposedtherethrough. In addition, the substrate 21 may be exposed in theelectrode pad region EP. Alternatively, the insulation layer 531 maycover the bottom of the hole 23 a, so that the electrode pad region EPcan be covered with the insulation layer 531.

Referring to FIG. 33e , the first electrode pad 535, first lowerextension 535 a and second extension 535 b are formed on the exposedregions of the first conductive type semiconductor layer 23 of the lightemitting structure. Further, a second electrode pad 733 is formed on theelectrode pad region EP, and upper extensions 533 a are formed in theopenings 531 a. Further, connectors 533 b are formed to connect thesecond electrode pad 733 to the upper extensions 533 a.

The upper extensions 533 a may be connected to the transparent electrodelayer 529 and be formed parallel to the first lower extension 535 a. Asa result, a light emitting diode is fabricated as shown in FIG. 31.

In the present exemplary embodiment, the light emitting structure isdivided into the two light emitting regions LE1, LE2, but is not limitedthereto. The light emitting structure may be divided into more than twolight emitting regions. Further, although the transparent electrodelayer 529 is formed after mesa-etching in the present exemplaryembodiment, the mesa-etching may be carried out after formation of thetransparent electrode layer 529. Moreover, although the hole 23 a isformed after mesa-etching in the present exemplary embodiment, themesa-etching may be carried out after formation of the hole 23 a.

As compared with the light emitting diode described with reference toFIGS. 24 and 25, the electrode pad region EP of the present exemplaryembodiment isolated from the light emitting structure is formed in thehole 23 a of the first conductive type semiconductor layer 23.Accordingly, the second electrode pad 733 is located on the substrate 21or on the insulation layer 531 on the substrate. The feature of formingthe electrode pad region EP in the hole 23 a of the first conductivetype semiconductor layer 23 may also be applied to the light emittingdiodes described with reference to FIGS. 26 and 27.

FIG. 34 is a plan view of a light emitting diode according to atwenty-third exemplary embodiment of the present invention, and FIGS.35a, 35b and 35c are cross-sectional views taken along lines A-A, B-Band C-C of FIG. 34, respectively.

Referring to FIGS. 34, 35 a, 35 b and 35 c, the light emitting diodeincludes a substrate 21, a light emitting structure including lightemitting regions LE1, LE2, a first electrode pad 835, a second electrodepad 833, and upper extensions 833 a. Further, the light emitting diodemay include a transparent electrode layer 829, an insulation layer 831,connectors 833 b, a first lower extension 835 a, and a second lowerextension 835 b. In addition, the light emitting structure includes afirst conductive type semiconductor layer 23, an active layer 25, and asecond conductive type semiconductor layer 27. Description of the samecomponents as those described in the above exemplary embodiments will beomitted.

The second conductive type semiconductor layer 27 and active layer 25 ofthe light emitting structure may be divided to define at least two lightemitting regions LE1, LE2. The light emitting regions LE1, LE2 may havea symmetrical structure and the dividing process may be carried out bymesa-etching. Specifically, the first conductive type semiconductorlayer 23 is exposed in a region crossing the center of the lightemitting structure by mesa-etching to divide the second conductive typesemiconductor layer 27 and active layer 25 into the two light emittingregions. Further, side surfaces of the light emitting structuresubjected to mesa-etching may be inclined at 30-70 degrees relative to asubstrate plane relative to a plane of the substrate 21.

The region crossing the center of the light emitting structure, that is,at least a portion of the first conductive type semiconductor layer 23between the light emitting regions is removed to expose a side surfaceof the first conductive type semiconductor layer 23.

In addition, a transparent electrode layer 829 may be located on thesecond conductive type semiconductor layer 27 of the light emittingstructure. The transparent electrode layer 529 may be formed of ITO orNi/Au and forms an ohmic contact with the second conductive typesemiconductor layer 27.

An insulation layer 831 may cover the second conductive typesemiconductor layer 27 (or the transparent electrode layer 829) of thelight emitting structure. The insulation layer 831 may also cover sidesurfaces of the second conductive type semiconductor layer 27 and activelayer 25, which are exposed by mesa-etching. In addition, the insulationlayer 831 may have openings 831 a which expose the transparent electrodelayer 829 on the light emitting regions LE1, LE2. The transparentelectrode layer 829 (or the second conductive type semiconductor layer27) is exposed through the openings 831 a. The insulation layer 831 maybe formed of any transparent material, for example SiO₂, through whichlight can be transmitted.

The first electrode pad 835 and the second electrode pad 833 may belocated on the substrate 21. The first electrode pad 835 may be locatedto face the second electrode pad 833, as shown in FIG. 34. The first andsecond electrode pads 835, 833 are bonding pads for wire bonding and mayhave a relatively wide area for wire bonding.

The first electrode pad 835 may be in contact with the substrate and beconnected to a side surface of the first conductive type semiconductorlayer 23 of the light emitting structure. Further, the first lowerextension 835 a may extend from the first electrode pad 835 towards thesecond electrode pad 833. The first lower extension 835 a is located onthe substrate 21 and connected to a side surface of the first conductivetype semiconductor layer 23. As shown in FIG. 34, the first lowerextension 835 a may be located between the light emitting regions LE1,LE2 and has a distal end near the second electrode pad 833. The firstlower extension 835 a may also be in contact with the substrate. Inaddition, the second lower extensions 835 b may extend from the firstelectrode pad 835 along an edge of the substrate 21. The second lowerextensions 835 b may also be in contact with the substrate and beconnected to the side surface of the first conductive type semiconductorlayer 23 of the light emitting structure.

As the first electrode pad 835, first lower extensions 835 a and secondlower extensions 835 b are connected to the side surface of the firstconductive type semiconductor layer 23, carriers may spread in a regionof the first conductive type semiconductor layer 23, which is locatedaway from the active layer 25, thereby allowing efficient currentspreading within the first conductive type semiconductor layer 23. Inaddition, as the first electrode pad 835, first lower extensions 835 aand second lower extensions 835 b are connected to the side surface ofthe first conductive type semiconductor layer 23, upper surfaces of thefirst electrode pad 835, first lower extensions 835 a and second lowerextensions 835 b may be located under the active layer 25, whichgenerates light. As a result, light laterally emitted from the activelayer 25 may be discharged without being absorbed by the first electrodepad 835, first lower extensions 835 a and second lower extensions 835 b.

The second electrode pad 833 is located on the substrate 21 and isisolated from the second conductive type semiconductor layer 27 of thelight emitting structure. The second electrode pad 833 may be locatedaway from a side surface of the second conductive type semiconductorlayer 27. For example, the second electrode pad 833 may be formed on thesubstrate 21 exposed through a hole 23 a in the first conductive typesemiconductor layer 23. In other words, the second electrode pad 833 maybe laterally separated from the first conductive type semiconductorlayer 23 of the light emitting structure. The second electrode pad 833may be in contact with the substrate 21 exposed through the hole 23 a.Further, an insulation layer 831 may be disposed between the secondelectrode pad 833 and the substrate 21. Alternatively, the secondelectrode pad may be formed above the first conductive typesemiconductor layer 23 with the insulation layer 831 disposed betweenthe second electrode pad 833 and the first conductive type semiconductorlayer 23.

The upper extensions 833 a are located on the light emitting regionsLE1, LE2. The upper extensions 833 a may be electrically connected tothe transparent electrode layer 829 (or the second conductive typesemiconductor layer 27) via the openings 831 a of the insulation layer831. The second conductive type semiconductor layer 27 may be exposedthrough the openings 831 a, and the upper extensions 833 a may bedirectly connected to the second conductive type semiconductor layer 27.The upper extensions 833 a are disposed to allow uniform currentspreading in the second conductive type semiconductor layer 27. Forexample, the upper extensions 833 a may extend parallel to each other.The upper extensions 833 a may be connected to the second electrode pad833 via connectors 833 b, respectively. The connectors 833 b areinsulated from the transparent electrode layer 829 (or the secondconductive type semiconductor layer 27) by the insulation layer 831. Theconnectors 833 b are insulated from the side surface of the lightemitting structure by the insulation layer 831.

The electrode pads 833, 835, upper extensions 833 a, connectors 833 b,and first and second lower extensions 835 a, 835 b may be formed of, butare not limited to, the same material, for example Cr/Au, by the sameprocess. Alternatively, the upper extensions 833 a and the secondelectrode pad 833 may be formed of different materials by differentprocesses.

In the present exemplary embodiment, the light emitting diode has asymmetrical structure relative to a line crossing the first electrodepad 835 and the second electrode pad 833, for example line B-B of FIG.34. The divided regions of the transparent electrode layer 829 and theupper extensions 833 a may be symmetrically disposed, and the secondlower extensions 835 b may also be symmetrically disposed. Accordingly,the light emitting diode may exhibit the same luminescencecharacteristics at both sides of the line crossing the first electrodepad 835 and the second electrode pad 833. As a result, the lightemitting structure of the light emitting diode is divided into two lightemitting regions, so the light emitting diode can prevent currentcrowding around a defect such as pin holes or thread dislocations,thereby achieving uniform current spreading.

FIGS. 36a, 36b, 36c, 36d and 36e are plan views illustrating a method ofmanufacturing a light emitting diode according to the twenty-thirdexemplary embodiment. Methods of forming semiconductor layers 23, 25,27, a transparent electrode layer 829 and an insulation layer 831 arewell known in the art and a detailed description thereof will be omittedherein. Any process, known now or not yet known, that can formsemiconductor layers 23, 25, 27, a transparent electrode layer 329 andan insulation layer 331, can be used to manufacture the light emittingdiode.

First, referring to FIG. 36a , semiconductor layers including an n-typesemiconductor layer 23, active layer 25 and second conductive typesemiconductor layer 27 are formed on a substrate 21. Then, thesemiconductor layers are subjected to mesa-etching to expose the firstconductive type semiconductor layer 23. The semiconductor layers mayhave inclined surfaces, for example, at 30-70 degrees relative to asubstrate plane. Here, as shown in FIG. 34, a region 30 a to be formedwith a first electrode pad 835, a region 30 b to be formed with a firstlower extension 835 a, and a region 30 c to be formed with a secondlower extension 835 b are exposed on the first conductive typesemiconductor layer 23. Here, an upper portion of an electrode padregion EP, on which the second electrode pad will be formed, and thefirst conductive type semiconductor layer 23 around the electrode padregion EP are exposed by mesa-etching. Accordingly, the secondconductive type semiconductor layer 27 and active layer 23 are dividedto define two light emitting regions LE1, LE2 by the mesa-etching, and aregion between the light emitting regions LE1, LE2 will be formed withthe first lower extension 835 a.

Referring to FIG. 36b , the substrate 21 is exposed by etching theexposed first conductive type semiconductor layer 23. As a result, thesubstrate 21 is exposed on the regions 30 a, 30 b, 30 c, on which thefirst electrode pad 835, first lower extension 835 a and secondextension 835 b will be respectively formed. Further, a hole 23 a may beformed to expose the substrate 21 by etching the first conductive typesemiconductor layer 23 of the electrode pad region EP. The hole 23 a maybe formed greater than the electrode pad region EP to encompass theelectrode pad region EP. The hole 23 a may be in communication with theregion 30 b on which the first lower extension 835 a will be formed. Inthis stage, the light emitting structure including the light emittingregions LE1, LE2 is formed.

Referring to FIG. 36c , a transparent electrode layer 829 may be formedon the second conductive type semiconductor layer 27 of the lightemitting regions LE1, LE2. The transparent electrode layer 829 may havea symmetrical structure relative to a line crossing the first electrodepad and the second electrode pad. The transparent electrode layer 829may be formed of ITO or Ni/Au and forms an ohmic contact with the secondconductive type semiconductor layer 27.

Referring to FIG. 36d , an insulation layer 831 is formed on the lightemitting structure. The insulation layer 831 covers the transparentelectrode layer 829 of the light emitting structure. The insulationlayer 831 may also cover side surfaces of the second conductive typesemiconductor layer 27 and active layer 25, which are exposed bymesa-etching, and may cover a sidewall of the hole 23 a. In addition,the insulation layer 831 is subjected to a patterning process to formopenings 831 a, which expose the transparent electrode layer 829 onlight emitting regions LE, LE2, via photolithography and etching. Theopenings 831 a exposing the transparent electrode layer 829 may besymmetrically formed parallel to each other. Further, the regions 30 a,30 b, 30 c of the first conductive type semiconductor layer 23, on whichthe first electrode pad 835, first lower extension 835 a and secondextension 835 b will be respectively formed, are also exposedtherethrough. In addition, the substrate 21 may be exposed in theelectrode pad region EP. Alternatively, the insulation layer 831 maycover the bottom of the hole 23 a, so that the electrode pad region EPcan be covered with the insulation layer 831.

Referring to FIG. 36e , the first electrode pad 835, first lowerextension 835 a and second extension 835 b are formed on the exposedregions of the substrate 21. Further, a second electrode pad 833 isformed on the substrate 21 of the electrode pad region EP, and upperextensions 833 a are formed in the openings 831 a. Further, connectors833 b are formed to connect the second electrode pad 833 to the upperextensions 833 a.

The first electrode pad 835, first lower extension 835 a and secondextension 835 b may be connected to the side surface of the firstconductive type semiconductor layer 23 of the light emitting structure,and upper surfaces of the first electrode pad 835, first lower extension835 a and second extension 835 b may be lower than the height of theactive layer 23. Further, the first electrode pad 835, first lowerextension 835 a and second extension 835 b may extend to an uppersurface of the first conductive type semiconductor layer 23 exposed bymesa-etching.

The upper extensions 833 a may be connected to the transparent electrodelayer 829 and be formed parallel to the first lower extension 835 a. Asa result, a light emitting diode is fabricated as shown in FIG. 34.

In the present exemplary embodiment, the light emitting structure isdivided into the two light emitting regions LE1, LE2, but is not limitedthereto. The light emitting structure may be divided into more than twolight emitting regions. Further, although the transparent electrodelayer 829 is formed after mesa-etching in the present exemplaryembodiment, the mesa-etching may be carried out after formation of thetransparent electrode layer 829. Moreover, although the hole 23 a isformed after mesa-etching in the present exemplary embodiment, themesa-etching may be carried out after formation of the hole 23 a.

FIG. 37 is a plan view of a light emitting diode according to atwenty-fourth exemplary embodiment of the present invention.

In the above exemplary embodiment of FIG. 34, the first and secondelectrode pads 835, 833 are disposed in a major axis direction of thelight emitting diode, and the light emitting regions LE1, LE2 aredivided in the major axis direction of the light emitting diode. In thepresent exemplary embodiment, however, the first and second electrodepads 835, 833 are disposed in a minor axis direction of the lightemitting diode, and the light emitting regions LE1, LE2 are divided inthe minor axis direction of the light emitting diode. Further, thetransparent electrode layers 829, upper extensions 853 a and lowerextensions 855 a are also disposed in a symmetrical structure relativeto a line crossing in the minor axis direction of the light emittingdiode.

Here, the upper extensions 853 a extend along an edge of the lightemitting diode to surround the light emitting diode and includeextensions 853 b extending inwardly from the edge of the light emittingdiode. Lower extensions 555 a extend outwardly from the interior of thelight emitting diode. Further, the lower extensions 555 a may bebifurcated to surround the extensions 553 b in associated light emittingregions, respectively. Each of the lower extensions 855 a is connectedto a side surface of the first conductive type semiconductor layer 23 ofthe light emitting structure.

The upper extensions 853 a are connected to the transparent electrodelayer 829 on the light emitting regions LE1, LE2 through the openings831 a of the insulation layer 831, and connected to the second electrodepad 853 through the connectors 853 b. The connectors 853 b are insulatedfrom the light emitting structure by the insulation layer 831.

As described with reference to FIG. 34, the second electrode pad 835 islocated on the substrate 21 and isolated from the second conductive typesemiconductor layer 27 of the light emitting structure.

In the present exemplary embodiment, the light emitting diode omits thefirst lower extension 835 a (see FIG. 34), which extends from the firstelectrode pad 855 to the second electrode pad 853.

FIG. 38 is a plan view of a light emitting diode according to a twentyfifth exemplary embodiment of the present invention.

Referring to FIG. 38, the light emitting diode of the present exemplaryembodiment is generally similar to the light emitting diode describedwith reference to FIG. 37. In the light emitting diode of the presentexemplary embodiment, however, lower extensions 865 a and upperextensions 863 a are arranged in a different manner than in the aboveexemplary embodiment.

Specifically, the lower extensions 865 a extend along an edge of thelight emitting diode and are bent to extend inwardly, and the upperextensions 863 a include two extensions on each of divided regions ofthe transparent electrode layer 829, which surround each of the lowerextensions 865 a extending inwardly.

The upper extensions 863 a are connected to the transparent electrodelayer 829 on light emitting regions LE1, LE2 through openings 831 a ofan insulation layer 831, and are connected to the second electrode pad853 through connectors 863 b. The connectors 863 b are insulated fromthe light emitting structure by the insulation layer 831.

In a conventional light emitting diode, a second electrode pad may belocated on a second conductive type semiconductor layer and electricallyconnected thereto. As a result, electric current is concentrated aroundthe second electrode pad, thereby inhibiting current spreading. On thecontrary, according to exemplary embodiments of the present invention,since the second electrode pad is isolated from a light emittingstructure or separated from a second conductive type semiconductor layerof the light emitting structure and a transparent electrode layer, it ispossible to prevent current crowding around the second electrode pad. Inaddition, the light emitting diode according to the exemplaryembodiments includes a plurality of first electrode pads to achievecurrent spreading around the first electrode pads. Further, the lightemitting diode according to the exemplary embodiments has plural lightemitting regions divided from one another, thereby achieving uniformcurrent spreading over the light emitting regions. Furthermore, thefirst electrode pad is connected to a side surface of the light emittingstructure, thereby achieving efficient current spreading in the firstconductive type semiconductor layer. Furthermore, since the firstelectrode pad is connected to a side surface of the first conductivetype semiconductor layer, an upper surface of the first electrode padmay be located under an active layer. Consequently, the light emittingdiodes may reduce optical loss by preventing absorption of light intothe first electrode pad when light generated from the active layer isemitted through the side surface of the light emitting structure.

Although the invention has been illustrated with reference to exemplaryembodiments in conjunction with the drawings, it will be apparent tothose skilled in the art that various modifications and changes can bemade in the invention without departing from the spirit and scope of theinvention. Therefore, it should be understood that the exemplaryembodiments are provided by way of illustration only and are given toprovide complete disclosure of the invention and to provide thoroughunderstanding of the invention to those skilled in the art. Thus, it isintended that the invention covers the modifications and variations ofthis invention provided they come within the scope of the appendedclaims and their equivalents.

What is claimed is:
 1. A light emitting diode, comprising: a substrate;a first conductive type semiconductor layer arranged on the substrate; amesa arranged on the first conductive type semiconductor layer andcomprising a second conductive type semiconductor layer and an activelayer between the first conductive type semiconductor layer and thesecond conductive type semiconductor layer; a transparent electrodedisposed on and in contact with the second conductive type semiconductorlayer; a first electrode pad electrically connected to the firstconductive type semiconductor layer; an insulation layer covering thetransparent electrode layer and an upper surface and side surfaces ofthe mesa, the insulation layer comprising an opening disposed above thetransparent electrode layer; a second electrode pad disposed on theinsulation layer; an upper extension disposed on and contacting thetransparent electrode layer; and a connector connecting the secondelectrode pad to the upper extension, wherein the side surfaces of themesa have a degree of inclination in the range of 30-70 degrees relativeto a plane of the substrate.
 2. The light emitting diode of claim 1,wherein the connector is spaced apart from the transparent electrodelayer, and wherein the second electrode pad is electrically connected tothe second conductive type semiconductor layer through the connector,the upper extension and the transparent electrode layer.
 3. The lightemitting diode of claim 1, wherein the insulation layer has at least twoopenings disposed on the transparent electrode layer.
 4. The lightemitting diode of claim 1, wherein the second electrode pad is arrangedon a region of the second conductive type semiconductor layer exposed bydividing the transparent electrode layer.
 5. The light emitting diode ofclaim 1, wherein the insulation layer is disposed between the secondelectrode pad and the transparent electrode layer to insulate the secondelectrode pad from the transparent electrode layer.
 6. The lightemitting diode of claim 1, wherein the transparent electrode layercomprises at least two regions separated from each other, and whereinmultiple upper extensions are electrically connected to the at least tworegions, respectively.
 7. The light emitting diode of claim 1, whereinthe first electrode pad is disposed facing the second electrode pad. 8.The light emitting diode of claim 7, further comprising: a first lowerextension connected to the first electrode pad, extending toward thesecond electrode pad and electrically connected to the first conductivetype semiconductor layer.
 9. The light emitting diode of claim 8,wherein a distal end of the first lower extension is closer to thesecond electrode pad than the first electrode pad.
 10. The lightemitting diode of claim 9, further comprising: a second lower extensionextending from the first electrode pad along an edge of the substrate.11. The light emitting diode of claim 8, wherein the first lowerextension and the upper extension are arranged parallel to one another.12. The light emitting diode of claim 1, wherein the transparentelectrode layer and the upper extension are arranged in a symmetricalstructure relative to an imaginary line bisecting the first electrodepad and the second electrode pad.
 13. The light emitting diode of claim1, wherein the upper extension is disposed on a bottom of the opening ofthe insulation layer.
 14. A light emitting diode, comprising: asubstrate: an N-type semiconductor layer disposed on the substrate; aP-type semiconductor layer disposed on the N-type semiconductor layer;an active layer disposed between the N-type semiconductor layer and theP-type semiconductor layer; a transparent electrode layer in an ohmiccontact with the P-type semiconductor layer; a first electrode padelectrically connected to the N-type semiconductor layer; a secondelectrode pad disposed on the transparent electrode layer; an insulationlayer disposed between the transparent electrode layer and the secondelectrode pad and insulating the second electrode pad from thetransparent electrode pad; and at least one upper extension electricallyconnected to the second electrode pad, disposed on and contacting thetransparent electrode layer, wherein the insulation layer covers thetransparent electrode layer, and has at least one opening on thetransparent electrode layer configured to electrically connect thesecond electrode pad to the P-type semiconductor layer.
 15. The lightemitting diode of claim 14, further comprising: a connector connectingthe upper extension to the second electrode pad, wherein the connectoris spaced apart from the transparent electrode layer.
 16. The lightemitting diode of claim 14, wherein the connector connects the secondelectrode pad disposed on the insulation layer to the upper extensiondisposed on a bottom of the opening.
 17. The light emitting diode ofclaim 16, wherein the connector is connected to the upper extensionthrough the opening.
 18. The light emitting diode of claim 14, furthercomprising: a first lower extension electrically connected to the firstelectrode pad, extending toward the second electrode pad, andelectrically connected to the N-type semiconductor layer, wherein thefirst electrode pad is disposed to face the second electrode pad. 19.The light emitting diode of claim 18, an end of the first lowerextension is closer to the second electrode pad than the first electrodepad.
 20. The light emitting diode of claim 19, further comprising: asecond lower extension electrically connected to the first electrodepad, wherein the second lower extension extends along an edge of thesubstrate.
 21. The light emitting diode of claim 14, further comprising:an indented portion extending inwardly from a side of the firstelectrode pad to a side of the second electrode pad, wherein the N-typesemiconductor layer is exposed by the indented portion.
 22. The lightemitting diode of claim 21, wherein the transparent electrode pad isarranged in a symmetrical structure relative to an imaginary linebisecting the first electrode pad and the second electrode pad.
 23. Thelight emitting diode of claim 14, further comprising: a first lowerextension electrically connected to the first electrode pad, wherein thefirst lower extension is electrically connected to the N-typesemiconductor layer in the indented portion.
 24. The light emittingdiode of claim 23, wherein the light emitting diode comprises at leasttwo upper extensions, and the at least two extensions are arranged in asymmetrical structure relative to an imaginary line bisecting the firstelectrode pad and the second electrode pad.
 25. The light emitting diodeof claim 24, further comprising: connectors connecting the upperextensions to the second electrode pad; wherein the connectors arespaced apart from the transparent electrode layer.
 26. The lightemitting diode of claim 24, wherein the first lower extension and theupper extensions are arranged parallel to one another.